Haemoglobin-derived iron-dependent hydroxyl radical formation in blood-induced joint damage: an in vitro study

Inflammatory diseases causing joint and bone destruction: rheumatoid arthritis and hemophilic arthropathy

Various diseases and conditions cause joint disorders. Osteoarthritis (OA) is characterized by the degeneration of articular cartilage, synovitis, and anabolic changes in surrounding bone tissues. In contrast, rheumatoid arthritis (RA) and hemophilic arthropathy (HA) display marked destruction of bone tissues caused by synovitis. RA is a representative autoimmune disease. The primary tissue of RA pathogenesis is the synovial membrane and involves various immune cells that produce catabolic cytokines and enzymes. Hemophilia is a genetic disorder caused by a deficiency in blood clotting factors. Recurrent intra-articular bleeding leads to chronic synovitis through excessive iron deposition and results in the destruction of affected joints. Although the triggers for these two joint diseases are completely different, many cytokines and enzymes are common in the pathogenesis of both RA and HA. This review focuses on the similarities between joint and bone destruction in RA and HA. The insights may be useful in developing better treatments for hemophilia patients with arthropathy and osteoporosis by leveraging advanced therapeutics for RA.

What is the rationale for mesenchymal stromal cells based therapies in the management of hemophilic arthropathies?

Hemophilia A and B are rare X-linked genetic bleeding disorders due to a complete or partial deficiency in the coagulation factors VIII or IX, respectively. The main treatment for hemophilia is prophylactic and based on coagulation factor replacement therapies. These treatments have significantly reduced bleeding and improved the patients' quality of life. Nevertheless, repeated joint bleedings (hemarthroses), even subclinical hemarthroses, can lead to hemophilic arthropathy (HA). This disabling condition is characterized by chronic pain due to synovial inflammation, cartilage and bone destruction requiring ultimately joint replacement. HA resembles to rheumatoid arthritis because of synovitis but HA is considered as having similarities with osteoarthritis as illustrated by the migration of immune cells, production of inflammatory cytokines, synovial hypertrophy and cartilage damage. Various drugs have been evaluated for the management of HA with limited success. The objective of the review is to discuss new therapeutic approaches with a special focus on the studies that have investigated the potential of using mesenchymal stromal cells (MSCs) in the management of HA. A systematic review of the literature has been made. Most of the studies have focused on the interest of MSCs for the delivery of missing factors VIII or IX but in some studies, more insight on the effect of MSC injection on synovial inflammation or cartilage structure were provided and put in perspective for possible clinical applications.

Aberrant methylation and expression of TNXB promote chondrocyte apoptosis and extracullar matrix degradation in hemophilic arthropathy via AKT signaling

Recurrent joint bleeding in hemophilia patients frequently causes hemophilic arthropathy (HA). Drastic degradation of cartilage is a major characteristic of HA, but its pathological mechanisms has not yet been clarified. In HA cartilages, we found server matrix degradation and increased expression of DNA methyltransferase proteins. We thus performed genome-wide DNA methylation analysis on human HA (N=5) and osteoarthritis (OA) (N=5) articular cartilages, and identified 1228 differentially methylated regions (DMRs) associated with HA. Functional enrichment analyses revealed the association between DMR genes (DMGs) and extracellular matrix (ECM) organization. Among these DMGs, Tenascin XB (TNXB) expression was down-regulated in human and mouse HA cartilages. The loss of Tnxb in F8-/- mouse cartilage provided a disease-promoting role in HA by augmenting cartilage degeneration and subchondral bone loss. Tnxb knockdown also promoted chondrocyte apoptosis and inhibited phosphorylation of AKT. Importantly, AKT agonist showed chondroprotective effects following Tnxb knockdown. Together, our findings indicate that exposure of cartilage to blood leads to alterations in DNA methylation, which is functionally related to ECM homeostasis, and further demonstrate a critical role of TNXB in HA cartilage degeneration by activating AKT signaling. These mechanistic insights allow development of potentially new strategies for HA cartilage protection.

Shedding light on the effects of blood on meniscus tissue: the role of mononuclear leukocytes in mediating meniscus catabolism

OBJECTIVE

Traumatic meniscal injuries can cause acute pain, hemarthrosis (bleeding into the joint), joint immobility, and post-traumatic osteoarthritis (PTOA). However, the exact mechanism(s) by which PTOA develops following meniscal injuries is unknown. Since meniscus tears commonly coincide with hemarthrosis, investigating the direct effects of blood and its constituents on meniscus tissue is warranted. The goal of this study was to determine the direct effects of blood and blood components on meniscus tissue catabolism.

METHODS

Porcine meniscus explants or primary meniscus cells were exposed to whole blood or various fractions of blood for 3 days to simulate blood exposure following injury. Explants were then washed and cultured for an additional 3 days prior to collection for biochemical analyses.

RESULTS

Whole blood increased matrix metalloproteinase (MMP) activity. Fractionation experiments revealed blood-derived red blood cells did not affect meniscus catabolism. Conversely, viable mononuclear leukocytes induced MMP activity, nitric oxide (NO) production, and loss of tissue sulfated glycosaminoglycan (sGAG) content, suggesting that these cells are mediating meniscus catabolism.

CONCLUSIONS

These findings highlight the potential challenges of meniscus healing in the presence of hemarthrosis and the need for further research to elucidate the in vivo effects of blood and blood-derived mononuclear leukocytes due to both hemarthrosis and blood-derived therapeutics.

Stromal cell-derived factor 1 alpha (SDF-1alfa) and cartilage oligomeric matrix protein (COMP): Two potential signature biomarkers of radiological detectable hemophilic arthropathy

INTRODUCTION

Hemophilia is a rare constitutional bleeding disorder due to a deficiency in Factor VIII or Factor IX. Recurrent hemarthroses, one of the major complications of the disease, lead to hemophilic arthropathy, a disabling condition that requires early diagnosis. Traditionally, clinical examination and plain film radiography have been used to diagnose hemophilic arthropathy. Magnetic resonance imaging (MRI) and ultrasound can be more useful for diagnosing soft-tissue changes. However, but each of these methods has limitations and diagnosis of arthropathy can be delayed.

AIM

The aim of this project was to assess plasmatic biomolecules indicative of osteo-cartilaginous damage in patients with hemophilia with or without known arthropathy, in order to improve the diagnosis of this major complication of the disease.

METHODS

In this monocentric retrospective study, 40 patients with hemophilia A or B, for whom a plasma sample was available, provided informed consent for further analyses (multiplex immunoassays and ELISA) and collection of relevant clinical information in their medical files. Correlations were sought for between biomarkers of interest and the severity of joint lesions assessed according to Pettersson's radiologic score.

RESULTS

Two biomarkers were identified, respectively SDF-1α and COMP. Their plasmatic levels were significantly increased in patients with arthropathy compared to controls and patients without arthropathy. These values correlated significantly with the Pettersson score in patients under regular prophylaxis.

CONCLUSION

Two plasma biomarkers have been identified that could help assess the presence and severity of hemophilic arthropathy.

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.

Red blood cell exposure increases chondrocyte susceptibility to oxidative stress following hemarthrosis

OBJECTIVE

The detrimental effects of blood exposure on articular tissues are well characterized, but the individual contributions of specific whole blood components are yet to be fully elucidated. Better understanding of mechanisms that drive cell and tissue damage in hemophilic arthropathy will inform novel therapeutic strategies. The studies here aimed to identify the specific contributions of intact and lysed red blood cells (RBCs) on cartilage and the therapeutic potential of Ferrostatin-1 in the context of lipid changes, oxidative stress, and ferroptosis.

METHODS

Changes to biochemical and mechanical properties following intact RBC treatment were assessed in human chondrocyte-based tissue-engineered cartilage constructs and validated against human cartilage explants. Chondrocyte monolayers were assayed for changes to intracellular lipid profiles and the presence of oxidative and ferroptotic mechanisms.

RESULTS

Markers of tissue breakdown were observed in cartilage constructs without parallel losses in DNA (control: 786.3 (102.2) ng/mg; RBCINT: 751 (126.4) ng/mg; P = 0.6279), implicating nonlethal chondrocyte responses to intact RBCs. Dose-dependent loss of viability in response to intact and lysed RBCs was observed in chondrocyte monolayers, with greater toxicity observed with lysates. Intact RBCs induced changes to chondrocyte lipid profiles, upregulating highly oxidizable fatty acids (e.g., FA 18:2) and matrix disrupting ceramides. RBC lysates induced cell death via oxidative mechanisms that resemble ferroptosis.

CONCLUSIONS

Intact RBCs induce intracellular phenotypic changes to chondrocytes that increase vulnerability to tissue damage while lysed RBCs have a more direct influence on chondrocyte death by mechanisms that are representative of ferroptosis.

Retrospective Analysis of Responders and Impaired Patients with Knee Osteoarthritis Treated with Two Consecutive Injections of Very Pure Platelet-Rich Plasma (PRP)

OBJECTIVES

To assess the effectiveness of two consecutive intraarticular injections of PRP to treat knee osteoarthritis (KOA), discriminating between responders and impaired patients.

METHODS

This retrospective study included 73 consecutive patients who were referred for two intra-articular PRP injections (one week apart) for treating symptomatic moderate/severe KOA. Biological characterization of the PRP, including platelets, leukocytes and erythrocytes, was evaluated. Patient's subjective symptoms were recorded before the treatment and 1 year after the second injection using pain VAS and WOMAC scores. Responders were defined by an improvement of 10 points on WOMAC.

RESULTS

At a 1-year follow up, we found 36 (49.3%) patients who fulfilled the criteria of responders, and 21 (28.8%) patients were impaired. A statistically and clinically significant global improvement of -29.2 ± 14.3 (p < 0.001) points in WOMAC score was observed 1 year after treatment in the responder group, with a higher response rate in patients with KL 2 (57.7%) compared to KL IV (28.6%). The percentage of patients with KL IV was higher in the impaired group (48.0%) compared to the responders (16.6%). As expected, the evaluation of the functionality of the knee in the impaired group indicates that it significantly worsened after one year from treatment (p = 0.027). However, the average pain score remained stable with no significant differences after 1 year (p = 0.843). No clinical complications or severe adverse events after the PRP injections were reported.

CONCLUSION

The present study suggests that two intra-articular injections of 10 mL of very pure PRP provide pain and functional improvement in symptomatic KOA.

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 value of radiosynoviorthesis for treatment of chronic synovitis in hemophilic joint disease

Chronic synovitis is contributing to the development of arthropathy in hemophilia A and B. In most patients with severe and moderate hemophilia, during lifetime, joint damage progresses despite early prophylaxis and intense treatment with coagulation factor concentrates. Recurrent hemorrhages into the joints and subclinical bleeding lead to chronic inflammation of the synovium, neoangiogenesis and remodeling, sustaining a vicious circle of bleeding-remodeling-bleeding and progression of osteochondral damage. Imaging techniques including ultrasound and MRI are able to early visualize synovitis and osteochondral changes. Early detection and sustained therapy of synovitis are important preconditions to prevent further deterioration of joint status. Chronic synovitis requires intensified substitution of coagulation factors and concomitant analgetic, antiphlogistic and physical therapy. The value of early radiosynoviorthesis (RSO) as effective method to control ongoing synovitis is discussed here. RSO is recommended as first choice therapy in case of persistant chronic synovitis, recorded in both national and international guidelines.

Which part of the blood in the knee joint is responsible for its detrimental effects? (An experimental study on the knee joint in rabbits)

AIM

This study aims to determine the potential causative elements which are responsible for the cartilage damage in case of frequent intra-articular bleeding and to evaluate the effects of intra-articular free iron and chelation of iron in the knee joint.

METHODS

Thirty-five New Zealand rabbits were randomly divided into five groups according to substances injected into their knee joints. Plasma (group I) and cellular components (group II) of the blood harvested from the rabbits, iron (ferric hydroxide sucrose) (group III), iron&chelator (group IV) and only chelator (deferoxamine mesylate) (group V) were injected into their right knees three times a week for 12 weeks. The joint surface was examined histologically according to the classification system modified from Colombo et al. The changes in the synovial tissue were evaluated according to the scoring system modified from Madhok et al.

RESULTS

Cartilage and synovial abnormality scores were significantly higher in all study groups when compared to their own controls (p < 0.0001). Cartilage scores of groups I and V were significantly lower when compared to groups III and IV (p = 0.002 for group I and p = 0.003 for group V). Synovial abnormality score of group I was significantly lower than scores of groups III and IV (p = 0.001); and of group V lower than groups III and IV (p = 0.003 and p = 0.001, respectively).

CONCLUSIONS

All substances tested in this study caused a certain amount of damage in the cartilage tissue and led to synovial abnormalities. Both iron and iron&chelator caused more damage in the cartilage and led to more advanced synovial changes when compared to the plasma component of blood and chelator itself. Influence of iron and iron&chelators were found to be similar showing that chelation was inadequate in antagonizing the detrimental effects of iron.

Post-traumatic knee osteoarthritis; the role of inflammation and hemarthrosis on disease progression

Knee injuries such as anterior cruciate ligament ruptures and meniscal injury are common and are most frequently sustained by young and active individuals. Knee injuries will lead to post-traumatic osteoarthritis (PTOA) in 25–50% of patients. Mechanical processes where historically believed to cause cartilage breakdown in PTOA patients. But there is increasing evidence suggesting a key role for inflammation in PTOA development. Inflammation in PTOA might be aggravated by hemarthrosis which frequently occurs in injured knees. Whereas mechanical symptoms (joint instability and locking of the knee) can be successfully treated by surgery, there still is an unmet need for anti-inflammatory therapies that prevent PTOA progression. In order to develop anti-inflammatory therapies for PTOA, more knowledge about the exact pathophysiological mechanisms and exact course of post-traumatic inflammation is needed to determine possible targets and timing of future therapies.

FGF23 and SOX9 expression in hemophilic cartilage: In vitro studies of the effects of iron

INTRODUCTION

Clarifying the links between iron and FGF23, SOX9 expression in chondrocytes would be helpful for comprehending articular cartilage degradation pathogenesis in blood-induced arthritis and exploring new protective methods.

AIM

The purpose of this study was to determine iron regulation of fibroblast growth factor 23 (FGF23) and SRY-box 9 (SOX9) in human chondrocytes, an area which is unexplored in blood-induced arthritis cartilage degradation pathogenesis.

METHODS

Expression of FGF23, SOX9, MMP13 and collagen Ⅱ in articular cartilage of patients with osteoarthritis (OA) or haemophilic arthritis (HA) was determined by western blot (WB). Iron induced FGF23 and SOX9 mRNA and protein expression in primary human normal chondrocyte cells (HUM-iCell-s018) was quantifified by qRT-PCR and WB, respectively.

RESULTS

We found that compared with OA patients, the expression of FGF23, MMP13 in articular cartilage of patients with HA was up-regulated, while the expression of SOX9, collagen Ⅱ was down-regulated. Iron induced FGF23 and suppressed SOX9 expression in chondrocytes in a dose-dependent manner.

CONCLUSIONS

These findings demonstrated that iron were involved in hemophilic cartilage lesion directly via changing cartilage phenotype through regulation of FGF23 and SOX9 expression in chondrocytes.

Pain in Hemophilia: Unexplored Role of Oxidative Stress

Hemophilia is the most common X-linked bleeding diathesis caused by the genetic deficiency of coagulation factors VIII or IX. Despite treatment advances and improvements in clinical management to prevent bleeding, management of acute and chronic pain remains to be established. Repeated bleeding of the joints leads to arthropathy, causing pain in hemophilia. However, mechanisms underlying the pathogenesis of pain in hemophilia remain underexamined. Herein, we describe the novel perspectives on the role for oxidative stress in the periphery and the central nervous system that may contribute to pain in hemophilia. Specifically, we cross examine preclinical and clinical studies that address the contribution of oxidative stress in hemophilia and related diseases that affect synovial tissue to induce acute and potentially chronic pain. This understanding would help provide potential treatable targets using antioxidants to ameliorate pain in hemophilia.

The Potential Role of Protease Systems in Hemophilic Arthropathy

Haemophilic arthropathy is characterised by joint damage following recurrent joint bleeds frequently observed in patients affected by the clotting disorder haemophilia. Joint bleeds or haemarthroses trigger inflammation in the synovial tissue which promotes damage to the articular cartilage. The plasminogen activation system is integral to fibrinolysis, and urokinase plasminogen activator or uPA in particular is strongly upregulated following haemarthroses. uPA is a serine protease that catalyses the production of plasmin, a broad-spectrum protease that can degrade fibrin as well as proteins of the joint extracellular matrix and cartilage. Both uPA and plasmin are able to proteolytically generate active forms of matrix metalloproteinases (MMPs). The MMPs are a family of >20 proteases that are secreted as inactive proenzymes and are activated extracellularly. MMPs are involved in degradation of all types of collagen and proteoglycans that constitute the extracellular matrix, which provides structural support to articular cartilage. The MMPs have an established role in joint destruction following rheumatoid arthritis (RA). They degrade cartilage and bone, indirectly promoting angiogenesis. MMPs are also implicated in the pathology of osteoarthritis (OA) characterized by degradation of the cartilage matrix that precipitates joint damage and deformity. HA shares a number of overlapping pathological characteristics with RA and OA. Here we discuss how the plasminogen activation system and MMPs might exacerbate joint damage in HA, lending insight into novel possible therapeutic targets to reduce co-morbidity of haemophilia.

The Impact of Trace Elements on Osteoarthritis

Osteoarthritis (OA) is a progressive degenerative disease characterized by cartilage degradation, synovial inflammation, subchondral sclerosis and osteophyte formation. It has a multifactorial etiology with potential contributions from heredity, endocrine function, abnormal mechanical load and nutrition. Of particular considerations are trace element status. Several trace elements, such as boron and magnesium are essential for normal development of the bone and joint in human. While cadmium correlates with the severity of OA. The present review focuses on the roles of trace elements (boron, cadmium, copper, iron, magnesium, manganese, selenium, zinc) in OA and explores the mechanisms by which they act.

Iron homeostasis in arthropathies: From pathogenesis to therapeutic potential

Iron is an essential element for proper functioning of cells within mammalian organ systems; in particular, iron homeostasis is critical for joint health. Excess iron can induce oxidative stress damage, associated with the pathogenesis of iron-storage and ageing-related diseases. Therefore, iron levels in body tissues and cells must be tightly regulated. In the past decades, excess iron content within joints has been found in some patients with joint diseases including hemophilic arthropathy, hemochromatosis arthropathy, and osteoarthritis (OA). Currently, increased evidence has shown that iron accumulation is closely associated with multiple pathological changes of these arthropathies. This review summarizes system-level and intracellular regulation of iron homeostasis, and emphasizes the role of iron in synovial alterations, cartilage degeneration, and subchondral bone of several arthropathies. Of note, we discuss the potential link between iron homeostasis and OA pathogenesis. Finally, we discuss the therapeutic potential of maintaining iron homeostasis in these arthropathies.

The Role of Hypertension in Cartilage Restoration: Increased Failure Rate After Autologous Chondrocyte Implantation but Not After Osteochondral Allograft Transplantation

Objectives. The purpose of this study was to examine whether patients with diagnosed hypertension have an increased risk of graft failure following cartilage repair with either autologous chondrocyte implantation (ACI) or osteochondral allograft transplantation (OCA). We hypothesized that hypertension is related to higher ACI and OCA graft failure. Design. Patients who underwent ACI or OCA transplantation between February 2009 and December 2016 were included in this study. Inclusion criteria were (1) at least 2 years' follow-up, (2) available information related to the living habits (smoking and medication status), and (3) available information related to the presence of hypertension, diabetes mellitus, or hyperlipidemia. To identify potential independent risk factors of graft failure, univariate screening was performed and factors with significance at a level of P < 0.1 were entered in multivariate logistic regression models. Results. A total of 368 patients (209 ACI and 159 OCA) were included into our study. In the ACI group, 61 patients' (29.1%) graft failed. Univariate screening identified older age, female gender, defect size, higher prevalence of hypertension, and smoking as a predictor of graft failure. Following, multivariate logistic regression revealed female gender (odds ratio [OR] 1.02, P = 0.048), defect size (OR 1.07, P = 0.035), and hypertension (OR 3.73, P = 0.023) as significant independent risk factors predicting graft failure after ACI. In the OCA group, 29 patients' (18.2%) graft failed and none of the included factors demonstrated to be a potential risk factor for graft failure. Conclusion. Hypertension, defect size, and female gender seem to predict ACI graft failure but not OCA failure.

Bleeding with iron deposition and vascular remodelling in subchondral cysts: A newly discovered feature unique to haemophilic arthropathy

INTRODUCTION

Joint iron accumulation is the incendiary factor triggering osteochondral destruction, synovial hypertrophy, inflammation, and vascular remodelling in haemophilic arthropathy (HA). Hemosiderin depositions have been described in synovium and, more recently, in cartilage. Clinical observations also suggest hemosiderin accumulation in subchondral cysts, implying cyst bleeding.

AIM

We explored associations between cystic iron accumulation, vascular remodelling and HA status to determine if cystic bleeding may contribute to HA progression.

METHODS

Thirty-six haemophilic joints (16 knees, 10 ankles, and 10 elbows; 31 adult patients with haemophilia A/B) were evaluated by magnetic resonance imaging (MRI) for subchondral cysts and hemosiderin. Cyst score (WORMS) and hemosiderin presence were compared between haemophilic and osteoarthritic knees, matched for the degree of arthritis (Kellgren-Lawrence score). Cystic iron accumulation, vascular remodelling and macrophage cell counts were also compared by immunohistochemistry in explanted joint tissues. In haemophilic knees, cyst number and extent of hemosiderin deposition were correlated with haemophilia joint health scores (HJHS).

RESULTS

Cystic hemosiderin was detected in 78% of haemophilic joints. Cyst score and presence of hemosiderin were significantly higher in haemophilic compared to osteoarthritic knees. Cyst score and presence of hemosiderin strongly correlated with HJHS. Moreover, iron deposition and vascular remodelling were significantly more pronounced within cysts in haemophilic compared to osteoarthritic knees, with similar total cell and macrophage count.

CONCLUSION

These findings suggest the presence of subchondral bleeding in haemophilia, contributing to poor joint health outcomes. Observations of bleeding into osseous structures are novel and should inform investigations of new therapies.

On-demand treatment with the iron chelator deferasirox is ineffective in preventing blood-induced joint damage in haemophilic mice

INTRODUCTION

Early intervention in the devastating process of haemophilic arthropathy (HA) is highly desirable, but no disease-modifying therapy is currently available. Considering the pivotal role of iron in the development of HA, iron chelation is considered a promising therapeutic approach. A previous study in haemophilic mice demonstrated that treatment with the iron chelator deferasirox (DFX) 8 weeks before joint bleed induction, attenuated cartilage damage upon blood exposure. However, in haemophilia patients this approach is not opportune given the unpredictable occurrence of hemarthroses.

AIM

To evaluate the effectiveness of on-demand DFX treatment, initiated immediately after joint bleed induction.

METHODS

A joint bleed was induced in 66 factor VIII-deficient mice by infra-patellar needle puncture. Mice were randomly assigned to treatment with either placebo (drinking water) or DFX (dissolved in drinking water) throughout the study. Five weeks after joint bleed induction, inflammation and cartilage damage were assessed histologically. Joints of ten bleed naive haemophilic mice served as controls.

RESULTS

A joint bleed resulted in significant inflammation and cartilage damage in the blood-exposed joint compared with those of control animals, in both the placebo and DFX group (all p = <.05). No differences in tibiofemoral or patellar inflammation (p = .305 and p = .787, respectively) nor cartilage damage (p = .265 and p = .802, respectively) were found between the blood-exposed joints of both treatment groups.

CONCLUSION

On-demand treatment with DFX does not prevent joint damage following blood exposure in haemophilic mice. DFX seems unable to reach the joint in time to exert its effect before the irreversible harmful process is initiated.

Haemophilia

Haemophilia A and B are rare congenital, recessive X-linked disorders caused by lack or deficiency of clotting factor VIII (FVIII) or IX (FIX), respectively. The severity of the disease depends on the reduction of levels of FVIII or FIX, which are determined by the type of the causative mutation in the genes encoding the factors (F8 and F9, respectively). The hallmark clinical characteristic, especially in untreated severe forms, is bleeding (spontaneous or after trauma) into major joints such as ankles, knees and elbows, which can result in the development of arthropathy. Intracranial bleeds and bleeds into internal organs may be life-threatening. The median life expectancy was ~30 years until the 1960s, but improved understanding of the disorder and development of efficacious therapy based on prophylactic replacement of the missing factor has caused a paradigm shift, and today individuals with haemophilia can look forward to a virtually normal life expectancy and quality of life. Nevertheless, the potential development of inhibitory antibodies to infused factor is still a major hurdle to overcome in a substantial proportion of patients. Finally, gene therapy for both types of haemophilia has progressed remarkably and could soon become a reality.

Blood in the joint: effects of hemarthrosis on meniscus health and repair techniques

Injury to the meniscus is common and frequently leads to the development of post-traumatic osteoarthritis (PTOA). Many times meniscus injuries occur coincident with anterior cruciate ligament (ACL) injuries and lead to a bloody joint effusion. Hemarthrosis, or bleeding into the joint, has been implicated in degeneration of joint tissues. The goal of this review paper is to understand the pathophysiology of blood-induced joint damage, the possible effects of blood on meniscus tissue, and the implications for current meniscus repair techniques that involve the introduction of blood-derived products into the joint. In this review, we illustrate the similarities in the pathophysiology of joint damage due to hemophilic arthropathy (HA) and osteoarthritis (OA). Although numerous studies have revealed the harmful effects of blood on cartilage and synovium, there is currently a gap in knowledge regarding the effects of hemarthrosis on meniscus tissue homeostasis, healing, and the development of PTOA following meniscus injury. Given that many meniscus repair techniques utilize blood-derived and marrow-derived products, it is essential to understand the effects of these factors on meniscus tissue and the whole joint organ to develop improved strategies to promote meniscus tissue repair and prevent PTOA development.

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

We 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.

Pathological mechanism of joint destruction in haemophilic arthropathy

Haemophilic arthropathy (HA), caused by intra-articular haemorrhage, is one of the most common complications in patients with haemophilia. Factor replacement therapy provides missing coagulation factors to prevent children with haemophilia from joint bleeding and decreases their risk for HA. However, haemophilia patients in developing countries are still suffering from HA due to insufficient replacement therapy. Symptoms such as pain and activity limitations caused by HA seriously affect the functional abilities and quality of life of patients with HA, causing a high disability rate in the haemophilia cohort. The pathological mechanism of HA is complicated because the whole pathological mainly involves hypertrophic synovitis, osteopenia, cartilage and bone destruction, and these pathological changes occur in parallel and interact with each other. Inflammation plays an important role in the whole complex pathological process, and iron, cytokines, growth factors and other factors are involved. This review summarizes the pathological mechanism of HA to provide background for clinical and basic research.

Joint hemorrhage accelerates cartilage degeneration in a rat immobilized knee model

Background

Joint hemorrhage is caused by trauma, ligament reconstruction surgery, and bleeding disorders such as hemophilia. Recurrence of hemorrhage in the joint space induces hemosiderotic synovitis and oxidative stress, resulting in both articular cartilage degeneration and arthropathy. Joint immobilization is a common treatment option for articular fractures accompanied by joint hemorrhage. Although joint hemorrhage has negative effects on the articular cartilage, there is no consensus on whether a reduction in joint hemorrhage would effectively prevent articular cartilage degeneration. The purpose of this study was to investigate the effect of joint hemorrhage combined with joint immobilization on articular cartilage degeneration in a rat immobilized knee model.

Methods

The knee joints of adult male rats were immobilized at the flexion using an internal fixator from 3 days to 8 weeks. The rats were randomly divided into the following groups: immobilized blood injection (Im-B) and immobilized-normal saline injection (Im-NS) groups. The cartilage was evaluated in two areas (contact and non-contact areas). The cartilage was used to assess chondrocyte count, Modified Mankin score, and cartilage thickness. The total RNA was extracted from the cartilage in both areas, and the expression of metalloproteinase (MMP)-8, MMP-13, interleukin (IL)-1β, and tumor necrosis factor (TNF)-α was measured by quantitative real-time polymerase chain reaction.

Results

The number of chondrocytes in the Im-B group significantly decreased in both areas, compared with that in the Im-NS group. Modified Mankin score from 4 to 8 weeks of the Im-B group was significantly higher than that of the Im-NS group only in the contact area. The expression of MMP-8 and MMP-13 from 2 to 4 weeks and TNF-α from 2 to 8 weeks significantly increased in the Im-B group compared with those in the Im-NS group, but there was no significant difference in IL-1β expression.

Conclusions

The results showed that joint hemorrhage exacerbated immobilization-induced articular cartilage degeneration. Drainage of a joint hemorrhage or avoidance of loading may help prevent cartilage degeneration during joint immobilization with a hemorrhage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03795-0.

Systemic iron overload exacerbates osteoarthritis in the strain 13 guinea pig

OBJECTIVE

Iron is emerging as a key player in aging-associated diseases due to its propensity for driving free radical formation. Studies examining the role of iron in the pathogenesis of primary osteoarthritis (OA) are limited. Our objective was to establish a direct relationship between excess iron and OA by administering iron dextran to a guinea pig strain with decreased propensity for developing this disease.

DESIGN

Twenty, 12-week-old Strain 13 guinea pigs received either iron dextran or dextran control intraperitoneally once weekly for 4 weeks; termination occurred at 16 weeks of age. Iron levels were determined systemically (serum and liver) and within diarthrodial joints [femoral head articular cartilage and infrapatellar fat pads (IFPs) of knee joints]. One knee was collected to score structural changes associated with OA via microcomputed tomography (microCT) and histology using published grading schemes. Articular cartilage and IFPs were harvested from contralateral knees for gene expression analyses.

RESULTS

Iron overload was confirmed systemically via increased serum iron and liver iron concentration. Articular cartilage and IFPs in the iron dextran group also had higher levels of iron. Excess iron worsened knee OA using both microCT and histologic scoring systems. Gene analyses revealed that exogenous iron altered the expression of iron trafficking proteins, select cytokines, and structural components of cartilage.

CONCLUSION

These results demonstrate that systemic iron overload caused cellular iron accumulation in the knee joint. This excess iron is associated with increased expression of local inflammatory mediators and early onset and progression of knee joint OA in Strain 13 animals.

Inhibition of Fenton reaction is a novel mechanism to explain the therapeutic effect of intra-articular injection of PRP in patients with chronic haemophilic synovitis

INTRODUCTION AND AIM

Haemarthroses cause major morbidity in haemophilia resulting in chronic haemophilic synovitis (CHS) and arthropathy. Oxidation of haemoglobin-coupled iron released in synovium after haemolysis induces chondrocytes death and cartilage damage, allowing postulate using iron-chelating drugs as potential therapeutic tool for haemophilic joint damage. Considering that albumin, the most abundant plasma protein, is a physiologic iron chelator, we aim to demonstrate that impediment of haemoglobin oxidation is exerted by plasma as a mechanism involved in the therapeutic effect of intra-articular injection of platelet-rich plasma in CHS.

METHODS

Oxidation of haemoglobin (Hb) to methaemoglobin (MeHb) through Fenton reaction was induced in vitro by addition of potassium ferricyanide in the presence or absence of peripheral blood-derived platelets-rich or platelets-poor plasma (PRP/PPP) or albumin. The relevance of in vitro findings was analysed in synovial fluid (SF) samples from one patient with CHS obtained before and after 6 months of PRP intra-articular injection.

RESULTS

MeHb formation was completely impaired either by of PPP, PRP or albumin indicating that PRP exerts an anti-oxidative effect, probably due by plasma albumin. Analysis of SF samples revealed the presence of MeHb levels and haemosiderin-laden macrophages in SF obtained before PRP treatment. Reduction of synovial MeHb, normalization of cellular composition and improvement of health joint haemophilic score, pain and bleeding episodes were registered after 6 months of PRP intra-articular injection.

CONCLUSION

Inhibition of Fenton reaction and the consequent normalization of joint cellular composition is a noncanonical mechanism underlying the therapeutic effect of PRP intra-articular injection in CHS.

Synovitis and synovectomy in haemophilia

Joint bleeds cause major morbidity in haemophilia patients. The synovial tissue is responsible for removal of blood remnants from the joint cavity. But blood components, especially iron, lead to a series of changes in the synovial tissue: inflammation, proliferation and neovascularization. These changes make the synovium vulnerable to subsequent bleeding and as such a vicious cycle of bleeding-synovitis-bleeding may develop leading to chronic synovitis. The initial step in the treatment is adequate clotting factor supplementation and immediate physiotherapeutic involvement. If these measures fail, synovectomy may be indicated. Non-surgical options are chemical and radioactive synovectomy. This is a relatively non-invasive procedure to do synovectomy, leading to a reduction in pain and joint bleeds. Radioactive synovectomy seems more effective than chemical synovectomy in larger joints. Surgical options are open and arthroscopic synovectomy. Open synovectomy has been found to decrease the incidence of breakthrough bleeds but at the cost of loss of joint motion. Use of arthroscopic synovectomy has been advocated to reduce bleeding episodes with less morbidity to extra-articular tissue and preservation of joint motion. Use of a continuous passive motion (CPM) machine and early mobilization can decrease the postoperative stiffness and promote early recovery. This review addresses the current understanding of synovitis and its treatment options with specific emphasis on chemical and radioactive synovectomy and surgical options.

Platelet Concentrates in Musculoskeletal Medicine

Platelet concentrates (PCs), mostly represented by platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) are autologous biological blood-derived products that may combine plasma/platelet-derived bioactive components, together with fibrin-forming protein able to create a natural three-dimensional scaffold. These types of products are safely used in clinical applications due to the autologous-derived source and the minimally invasive application procedure. In this narrative review, we focus on three main topics concerning the use of platelet concentrate for treating musculoskeletal conditions: (a) the different procedures to prepare PCs, (b) the composition of PCs that is related to the type of methodological procedure adopted and (c) the clinical application in musculoskeletal medicine, efficacy and main limits of the different studies.

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

Introduction: 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 CD^11b+ 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.

Intracellular iron uptake is favored in Hfe-KO mouse primary chondrocytes mimicking an osteoarthritis-related phenotype

HFE-hemochromatosis is a disease characterized by a systemic iron overload phenotype mainly associated with mutations in the HFE protein (HFE) gene. Osteoarthritis (OA) has been reported as one of the most prevalent complications in HFE-hemochromatosis patients, but the mechanisms associated with its onset and progression remain incompletely understood. In this study, we have characterized the response to high iron concentrations of a primary culture of articular chondrocytes isolated from newborn Hfe-KO mice and compared the results with that of a similar experiment developed in cells from C57BL/6 wild-type (wt) mice. Our data provide evidence that both wt- and Hfe-KO-derived chondrocytes, when exposed to 50 μM iron, develop characteristics of an OA-related phenotype, such as an increased expression of metalloproteases, a decreased extracellular matrix production, and a lower expression level of aggrecan. In addition, Hfe-KO cells also showed an increased expression of iron metabolism markers and MMP3, indicating an increased susceptibility to intracellular iron accumulation and higher levels of chondrocyte catabolism. Accordingly, upon treatment with 50 μM iron, these chondrocytes were found to preferentially differentiate toward hypertrophy with increased expression of collagen I and transferrin and downregulation of SRY (sex-determining region Y)-box containing gene 9 (Sox9). In conclusion, high iron exposure can compromise chondrocyte metabolism, which, when simultaneously affected by an Hfe loss of function, appears to be more susceptible to the establishment of an OA-related phenotype.

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 349.1 ng/mL (232.8-415.6 ng/mL) and in OA patients 148.3 ng/mL (112.1-275.3 ng/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.

Hydrostatic pressure-generated reactive oxygen species induce osteoarthritic conditions in cartilage pellet cultures

Osteoarthritis (OA) is one of the most common causes of disability and represents a major socio-economic burden. Despite intensive research, the molecular mechanisms responsible for the initiation and progression of OA remain inconclusive. In recent years experimental findings revealed elevated levels of reactive oxygen species (ROS) as a major factor contributing to the onset and progression of OA. Hence, we designed a hydrostatic pressure bioreactor system that is capable of stimulating cartilage cell cultures with elevated ROS levels. Increased ROS levels in the media did not only lead to an inhibition of glycosaminoglycans and collagen II formation but also to a reduction of already formed glycosaminoglycans and collagen II in chondrogenic mesenchymal stem cell pellet cultures. These effects were associated with the elevated activity of matrix metalloproteinases as well as the increased expression of several inflammatory cytokines. ROS activated different signaling pathways including PI3K/Akt and MAPK/ERK which are known to be involved in OA initiation and progression. Utilizing the presented bioreactor system, an OA in vitro model based on the generation of ROS was developed that enables the further investigation of ROS effects on cartilage degradation but can also be used as a versatile tool for anti-oxidative drug testing.

Joint disease in haemophilia: Pathophysiology, pain and imaging

Haemarthroses cause major morbidity in patients with haemophilia. Blood has devastating effects on all joint components, resulting in synovitis, osteochondral degeneration and ultimately end-stage haemophilic arthropathy. Key players in this process are iron and inflammation. Preventing joint bleeds is of utmost importance to maintain joint health as targeted therapies directed against blood-induced inflammation and iron-mediated processes are lacking. Joint bleeds result in acute pain as well as chronic pain due to synovitis or arthropathy. Acute pain originates from nociceptors activated by tissue damage. In chronic inflammation, central and peripheral sensitization of nociceptors might occur resulting in chronic pain. This also triggers a series of brain disorders such as emotional fear, anxiety, mood depression and impairment of cognitive functions. Treatment of haemophilia-related pain not only consists of analgesics, but also of exercise, education and in selected cases antidepressants and anticonvulsants. For objective assessment of joint structural outcome and detecting earlier changes of haemophilic arthropathy, both ultrasound (US) and magnetic resonance (MR) imaging have shown valuable. Both can be considered equally able to reveal signs of disease activity. MR imaging is able to visualize haemosiderin deposition and is more comprehensive in depicting osteochondral changes. Disadvantages of MR imaging are the duration of the examination, evaluation of a single joint at a time, costs and may require sedation, and it may need intraarticular contrast injection to depict initial osteochondral changes with accuracy. As such, US is a more useful screening tool and can be used for repeated follow-up examinations.

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.

Time-Dependent Effects on Synovial Fluid Composition During the Acute Phase of Human Intra-articular Ankle Fracture

BACKGROUND

The study objective was to examine the effect of time and fracture severity on the undiluted synovial fluid (SF) microenvironment during the acute phase following intra-articular fracture (IAF) of the human ankle.

METHODS

Ankle SF from 54 patients with an acute IAF was analyzed for concentrations of 10 cytokines, 5 matrix metalloproteinases, 2 products of cartilage catabolism, and combined products of heme metabolism. All analytes were correlated with time from fracture and further analyzed for an effect of 3 time subgroups (0-2 days, 3-9 days, and ≥10 days) corresponding to timepoints for clinical ankle fracture interventions. The effect of fracture severity was determined by grouping SF according to the number of radiographic intra-articular fracture lines.

RESULTS

Fifteen of 18 analytes were significantly correlated with time. Temporal grouping of SF revealed an initial (0-2 days) spike of pro-inflammatory (IL-12p70, IL-1β, IL-6) and anti-inflammatory (IL-10 and IL-4) cytokines, matrix metalloproteinases (MMP) MMP-9, and sGAG, followed immediately (3-9 days) by products of heme metabolism and an unchallenged surge in mediators and products of cartilage catabolism (MMP-1, MMP-2, MMP-3, MMP-10, and CTX-II). After 10 days, there was a decrease in pro- and anti-inflammatory cytokines but a persistence of mediators of ECM catabolism. There was no clear relationship between the number of fracture lines and SF levels of analytes.

CONCLUSIONS

This study demonstrated acute temporal fluctuations following ankle IAF resulting in an overall catabolic environment by 10 days post-fracture and supports consideration of an early evacuation of the joint space to reduce the intra-articular inflammatory burden. Clinical Relavence: This study contributes to the understanding of the intra-articular events that potentially contribute to the development of posttraumatic osteoarthritis acutely following IAF in the ankle.

A fusion protein of interleukin-4 and interleukin-10 protects against blood-induced cartilage damage in vitro and in vivo

Essentials Targeted treatment for hemophilic arthropathy, still causing significant morbidity, is lacking. This study evaluates the efficacy of a fusion of protein of interleukin(IL)-4 and IL-10. In vitro the fusion protein prevents blood-induced cartilage damage in a dose-dependent manner. In hemophilic mice, the IL4-10 fusion protein ameliorates cartilage damage upon joint bleeding.

SUMMARY

Background Joint damage still causes significant morbidity in hemophilia. It results from synovial inflammation and direct cartilage-degenerating properties of blood components. Interleukin (IL)-4 and IL-10 have been shown to protect cartilage from blood-induced damage. Recently an IL4-10 fusion protein has been developed to combine the function of IL-4 and IL-10 and increase their bioavailability. Objectives In this study we evaluate whether this IL4-10 fusion protein protects against blood-induced joint damage. Methods In vitro, human cartilage explants were exposed to whole blood and simultaneously to a broad concentration range of the IL4-10 fusion protein. Effects on cartilage matrix turnover were compared with the individual cytokines. Moreover, the influence of the fusion protein and its individual components on IL-1β and IL-6 production was investigated. In hemophilia A mice, the effect of intra-articular treatment on synovitis and cartilage damage resulting from joint bleeding was evaluated by histochemistry. Results In vitro, the fusion protein prevented blood-induced cartilage damage in a dose-dependent manner, with equal effectiveness to the combination of the separate cytokines. In whole blood cultures 10 ng mL-1 fusion protein completely blocked the production of IL-1β and IL-6 by monocytes/macrophages. In hemophilic mice, intra-articular injection of IL-4 and IL-10 did not influence synovitis or cartilage degeneration. In contrast, equimolar amounts of the fusion protein attenuated cartilage damage upon repeated joint bleeding, although synovial inflammation was hardly affected. Conclusions Overall, this study shows that the IL4-10 fusion protein prevents blood-induced cartilage damage in vitro and ameliorates cartilage degeneration upon joint bleeding in hemophilic mice.

Pathophysiology of Hemophilic Arthropathy

Spontaneous joint bleeding and repeated hemarthroses lead to hemophilic arthropathy—a debilitating disease with a significant negative impact on mobility and quality of life. Iron, cytokines, and angiogenic growth factors play a pivotal role in the onset of the inflammatory process that involves the synovial tissue, articular cartilage, and subchondral bone, with early damages and molecular changes determining the perpetuation of a chronic inflammatory condition. Synovitis is one of the earliest complications of hemarthrosis, and is characterized by synovial hypertrophy, migration of inflammatory cells, and a high degree of neo-angiogenesis with subsequent bleeding. The pathogenic mechanisms and molecular pathways by which blood in the joint cavity causes articular cartilage and subchondral bone destruction have yet to be fully elucidated. Both cytokines and matrix metalloproteinases and hydroxyl radicals may induce chondrocyte apoptosis. Members of the tumor necrosis factor receptor superfamily (such as the molecular triad: osteoprotegerin—OPG; receptor activator of nuclear factor κB—RANK; RANK ligand—RANKL) seem instead to play a major role in the inflammatory process. These pathogenic processes interact with each other and ultimately lead to a fibrotic joint and the disabling condition characteristic of hemophilic arthropathy.

The importance of genetic factors for the development of arthropathy: a longitudinal study of children and adolescents with haemophilia A

Haemophilia A is a congenital bleeding disorder characterised by recurrent haemorrhages into the major joints. Haemophilic arthropathy is a well-established outcome of recurrent joint bleeding; however, it is clear that multiple factors determine the extent and severity of its occurrence. We sought to identify genetic factors related to abnormalities in range of motion (ROM) in the knees, ankles and elbows in a cohort of children and adolescents with haemophilia A not treated primarily with regular prophylaxis. Using data from the Haemophilia Growth and Development Study, we examined associations between 13,342 genetic markers and ROM scores measured at six-month intervals for up to seven years. As a first step, ordered logistic regression models were fit for each joint separately. A subset of SNP markers showing significant effects (p<0.01) on the right and left sides for at least two joints were included in a full model fit using a multivariate generalised linear mixed model assuming an ordinal response. The models contained all ROM scores obtained at all visits. Twenty-five markers analysed in the full model showed either increased or decreased risk of ROM abnormalities at the p<0.001 level. Several genes identified at either the first or second stage of the analysis have been associated with arthritis in a variety of large studies. Our results support the likelihood that risk for haemophilic arthropathy is associated with genetic factors, the identification of which holds promise for further advancing the individualisation of treatment.

Muscle Injuries and Repair: What's New on the Horizon!

Although we recognize the many advantages of improved musculoskeletal health, we also note that our ability to sustain this health and to maintain quality of life in an aging population is currently deficient. However, global efforts have produced numerous advances in tissue engineering and regenerative medicine that will collectively serve to fill this deficiency in the near future. The purpose of this review is to highlight our current knowledge, to outline our recent advances, and to discuss the evolving paradigms in skeletal muscle injury and repair.

Cartilage Repair in the Inflamed Joint: Considerations for Biological Augmentation Toward Tissue Regeneration

Cartilage repair/regeneration procedures (e.g., microfracture, autologous chondrocyte implantation [ACI]) typically result in a satisfactory outcome in selected patients. However, the vast majority of patients with chronic symptoms and, in general, a more diseased joint, do not benefit from these surgical techniques. The aims of this work were to (1) review factors negatively influencing the joint environment; (2) review current adjuvant therapies that can be used to improve results of cartilage repair/regeneration procedures in patients with more diseased joints, (3) outline future lines of research and promising experimental approaches. Chronicity of symptoms and advancing patient age appear to be the most relevant factors negatively affecting clinical outcome of cartilage repair/regeneration. Preliminary experience with hyaluronic acid, platelet-rich plasma, and mesenchymal stem cell has been positive but there is no strong evidence supporting the use of these products and this requires further assessment with high-quality, prospective clinical trials. The use of a Tissue Therapy strategy, based on more mature engineered tissues, holds promise to tackle limitations of standard ACI procedures. Current research has highlighted the need for more targeted therapies, and (1) induction of tolerance with granulocyte colony-stimulating factor (G-CSF) or by preventing IL-6 downregulation; (2) combined IL-4 and IL-10 local release; and (3) selective activation of the prostaglandin E2 (PGE2) signaling appear to be the most promising innovative strategies. For older patients and for those with chronic symptoms, adjuvant therapies are needed in combination with microfracture and ACI.

Advances and challenges in hemophilic arthropathy

Hemophilic arthropathy is a form of joint disease that develops secondary to joint bleeding and presents with synovial hypertrophy, cartilage and bony destruction. The arthropathy can develop despite clotting factor replacement and is especially disabling in the aging population. Pathobiological tissue changes are triggered by release of hemoglobin and iron deposition in the joint, but the sequence of events and the molecular mechanisms resulting in joint deterioration are incompletely understood. Treatment options other than clotting factor replacement are limited. Improvements in the treatment of hemophilia necessitate a better understanding of the processes that lead to this disabling condition and better diagnostic tools. Towards that end, studies of the molecular mechanisms leading to the arthropathy, as well as the development of sensitive imaging techniques and biomarkers are needed. These will pave the way to identify the cause of acute pain such as joint bleeding or synovitis, detect early, potentially reversible structural changes, and predict progression of disease. This review describes current imaging techniques and the development of high resolution musculoskeletal ultrasound with power Doppler to afford point-of-care diagnosis and management, the potential utility of diagnostic biomarkers, and summarizes our current knowledge of the pathobiology of hemophilic arthropathy.

IL-1β, in contrast to TNFα, is pivotal in blood-induced cartilage damage and is a potential target for therapy

Joint bleeding after (sports) trauma, after major joint surgery, or as seen in hemophilia in general leads to arthropathy. Joint degeneration is considered to result from the direct effects of blood components on cartilage and indirectly from synovial inflammation. Blood-provided proinflammatory cytokines trigger chondrocytes and induce the production of cartilage-degrading proteases. In the presence of erythrocyte-derived iron, cytokines stimulate radical formation in the vicinity of chondrocytes inducing apoptosis. To unravel the role of interleukin (IL) 1β and tumor necrosis factor (TNF) α in the pathogenesis of this blood-induced cartilage damage, the effect of antagonizing these cytokines was examined in human in vitro cultures. Addition of recombinant human IL-1β monoclonal antibody or IL-1 receptor antagonist resulted in a dose- and time-dependent protection of cartilage from blood-induced damage. In higher concentrations, almost complete normalization of cartilage matrix proteoglycan turnover was achieved. This was accompanied by a reduction in IL-1β and IL-6 production in whole blood cultures, whereas TNFα production remained unaffected. Interestingly, addition of a TNFα monoclonal antibody, although demonstrated to inhibit the direct (transient) effects of TNFα on cartilage, exhibited no effect on blood-induced (prolonged) cartilage damage. It is demonstrated that IL-1β is crucial in the development of blood-induced joint damage, whereas TNFα is not. This hierarchical position of IL-1β in blood-induced joint damage warrants studies on targeting IL-1β to potentially prevent joint degeneration after a joint bleed.

Five in one therapy for graded treatment of haemophilic arthritis

INTRODUCTION

Haemophilic arthritis is the most universal clinical appearance of haemophilia. Treatment of this disease has become an important and difficult issue worldwide until recently.

OBJECTIVE

To investigate the efficacy and safety of five in one therapy for graded treatment of haemophilic arthritis.

METHODS

Haemophilic arthritis was classified into grades I-IV according to severity and the standards of De Palma and Cotler. Under no application of FVIII/FIX replacement therapy state, the effect of five in one therapy (intra-articular cavity drug injection, oral drug preparation, physiotherapy, and prevention of haemorrhage and infection evoked by puncture) was observed in 1527 affected joints of 750 cases of haemophilic arthritis.

RESULTS

After 20 days treatment, all grade I and II, 94.98% of grade III and 56.16% of grade IV affected joints were completely relieved; 5.02% of grade III and 41.47% of grade IV affected joints were basically relieved; and 2.38% of grade IV were partially relieved. This resulted in short-term complete and basic relief of 98.56% (1505/1527) of all affected joints. After follow-up of 1-6 years, 86.97% of the affected joints were completely relieved, without any adverse reaction or complication.

CONCLUSION

The results suggest that five in one therapy is safe and effective for treatment of haemophilic arthritis, and provides a convenient, cost-effective way of preventing and treating deformity caused by haemophilic arthritis.