Validation of a radiographic scoring system for haemochromatosis arthropathy

Analysis of Hand Joint Space Morphology in Women and Men with Hereditary Hemochromatosis

Hereditary hemochromatosis (HH) causes unbalanced iron deposition in many organs including the joints leading to severe cartilage loss and bone damage in the metacarpophalangeal joints (MCPJ). High-resolution peripheral quantitative computed tomography (HR-pQCT) and its joint space width (JSW) quantification algorithm quantifies in vivo 3D joint morphology. We therefore aimed to (i) determine feasibility and performance of the JSW algorithm in HH, (ii) quantify joint space morphology, and (iii) investigate the relationship between morphological and clinical parameters in HH. Here, we performed an exploratory study on 24 HH patients and sex- and age-matched controls using HR-pQCT imaging of MCPJ. Mineralized bone structure was automatically segmented from the grayscale image data and periosteal surface bone masks and joint space masks were generated. Mean, minimal, and maximal joint space width (JSW; JSW.MIN; JSW.MAX), JSW heterogeneity (JSW.SD), JSW asymmetry (JSW.AS), and joint space volume (JSV) were computed. Demographics and, for HH patients, disease-specific parameters were recorded. Segmentation of JS was very good with 79.7% of MCPJs successfully segmented at first attempt and 20.3% requiring semi-manual correction. HH men showed larger JSV at all MCPs (+ 25.4% < JSV <  + 41.8%, p < 0.05), larger JSW.MAX at MCP 3-4 (+ 14%, 0.006 < p < 0.062), and wider JSW (+ 13%, p = 0.043) at MCP 4 relative to HH women. Compared to controls, both HH men and HH women showed larger JSW.AS and smaller JSW.MIN at all MCP levels, reaching significance for HH men at MCP 2 and 3 (JSW.AS: + 323% < JSW.AS <  + 359%, 0.020 < p < 0.043; JSW.MIN: - 216% < JSW.MIN < - 225%, p < 0.043), and for women at MCP 3 (JSW.AS: + 180%, p = 0.025; JSW.MIN: - 41.8%, p = 0.022). Time since HH diagnosis was correlated positively with MCP 4 JSW.AS and JSW.SD (0.463 < ρ < 0.499, p < 0.040), and the number of phlebotomies since diagnosis was correlated with JSW.SD at all MCPs (0.432 < ρ < 0.535, p < 0.050). HR-pQCT-based JSW quantification in MCPJ of HH patients is feasible, performs well even in narrow JS, and allows to define the microstructural joint burden of HH.

EASL Clinical Practice Guidelines on haemochromatosis

Haemochromatosis is characterised by elevated transferrin saturation (TSAT) and progressive iron loading that mainly affects the liver. Early diagnosis and treatment by phlebotomy can prevent cirrhosis, hepatocellular carcinoma, diabetes, arthropathy and other complications. In patients homozygous for p.Cys282Tyr in HFE, provisional iron overload based on serum iron parameters (TSAT >45% and ferritin >200 μg/L in females and TSAT >50% and ferritin >300 μg/L in males and postmenopausal women) is sufficient to diagnose haemochromatosis. In patients with high TSAT and elevated ferritin but other HFE genotypes, diagnosis requires the presence of hepatic iron overload on MRI or liver biopsy. The stage of liver fibrosis and other end-organ damage should be carefully assessed at diagnosis because they determine disease management. Patients with advanced fibrosis should be included in a screening programme for hepatocellular carcinoma. Treatment targets for phlebotomy are ferritin <50 μg/L during the induction phase and <100 μg/L during the maintenance phase.

The role of disrupted iron homeostasis in the development and progression of arthropathy

Arthropathy or joint disease leads to significant pain and disability irrespective of etiology. Clinical and experimental evidence point to the presence of considerable links between arthropathy and iron overload. Previous work has suggested that iron accumulation in the joints is often associated with increased oxidative stress, disrupted matrix metabolism, and cartilage degeneration. However, key issues regarding the role of iron overload in the pathogenesis of arthropathy remain ambiguous. For example, significant gaps in our knowledge of the primary cellular targets of iron overload-induced damage and the exact molecular mechanism through which disrupted iron homeostasis leads to joint damage still exist. The exact signaling pathway that links iron metabolism and cellular damage in arthropathy also remains largely unmapped. In this review, we focus on the relationship between iron overload and arthropathy with special emphasis on the adversarial relationship between iron that accumulates in the joints over time and cartilage homeostasis. A better understanding of the mechanisms and pathways underlying iron-induced cartilage degeneration may help in defining new prognostic markers and therapeutic targets in arthropathy.

Iron Overload Induces Oxidative Stress, Cell Cycle Arrest and Apoptosis in Chondrocytes

Clinical and experimental evidence point to the presence of considerable links between arthropathy, osteoarthritis (OA) in particular, and iron overload possibly due to oxidative stress and tissue damage. However, the specific cellular targets of iron overload-related oxidative stress in OA remain ambiguous. We examined the effects of iron overload on chondrocyte health using the C-20/A4 chondrocyte cell line. Cells were treated with increasing concentrations of ferric ammonium citrate (FAC) to mimic iron overload in vitro. Treated cells were assessed for cell viability, cycling, apoptosis, collagen II synthesis, and oxidative stress along with cellular iron content and the expression of key iron regulatory genes. FAC treatment resulted in an increase in ferritin expression and a significant decrease in the expression of hepcidin, ferroportin, transferrin receptors 1 (TfR1) and TfR2. Increased labile iron content was also evident, especially in cells treated with high FAC at 24 h. High doses of FAC treatment also induced higher levels of reactive oxygen species, reduced collagen II production, disrupted cell cycle and higher cell death as compared with untreated controls. In conclusion, findings presented here demonstrate that iron overload disrupts cellular iron homeostasis, which compromises the functional integrity of chondrocytes and leads to oxidative stress and apoptosis.

Rheumatologie und Hepatologie interdisziplinär

Rheumatologische und hepatologische Erkrankungen haben einige Überschneidungen, die für Behandler aus beiden Disziplinen relevant sind. In dieser Übersicht wird ein Schlaglicht auf 2 Erkrankungen geworfen, die sich an der Schnittstelle befinden: Arthropathie bei Hämochromatose und Systemische Sklerose bei Primär Biliärer Cholangitis. Daneben werden hepatologische Fragestellungen bei rheumatologischer Therapie beleuchtet.

Bone and joint complications in patients with hereditary hemochromatosis: a cross-sectional study of 93 patients

Background

The aim of this study was to determine the frequency and characteristics of bone and joint complications, specifically bone fragility, joint replacement surgery, and arthropathy, in hereditary hemochromatosis (HH) and related factors.

Methods

This study was a cross-sectional observational study of 93 patients with HH. Radiographs of the hands, wrists, knees, and ankles were scored for joint space narrowing, erosions and cysts, osteophytes, and chondrocalcinosis. Prevalent (vertebral and non-vertebral) fragility fractures were recorded and bone mineral density (BMD) was systematically evaluated by dual energy X-ray absorptiometry. Bone fragility was defined as (i) a T-score ⩽ -2.5 at any site with or without a prevalent fragility fracture, or (ii) a T-score between -1.0 and -2.5 at any site and a prevalent fragility fracture.

Results

The mean age of the patients was 60.0 (11.2) years, and 58.0% of them were men. The frequency of radiographic MCP2-3 arthropathy was 37.6% (95% CI 0.28-0.48). Radiographic MCP2-3 arthropathy was independently associated with older age [OR 1.17 (1.09-1.26) per year, p < 0.0001], male sex [OR 3.89 (1.17-12.97), p = 0.027] and C282Y+/+ genotype [OR 4.78 (1.46-15.68), p = 0.010]. The frequency of joint replacement surgery was 12.9% (95% CI 0.07-0.21). The frequency of bone fragility was 20.4% (95% CI 0.13-0.30). Bone fragility was independently associated with hepatic cirrhosis [OR 8.20 (1.74-38.68), p = 0.008].

Discussion

Radiographic MCP2-3 arthropathy was found to occur in 37.6% of patients with HH. The association observed between this form of arthropathy and C282Y homozygosity, male sex, and older age suggests that demographic characteristics and genetic background are likely to be major determinants of this joint disorder and play a more important role than severity of iron overload. Bone fragility was observed in a fifth of the patients with HH, independently of genetic background and severity of iron overload, and was strongly associated with hepatic cirrhosis.

Conclusion

Future investigations should focus on pathogenesis and early identification of patients at risk of developing bone and joint complications secondary to HH.

Hand X-ray examination in two planes is not required for radiographic assessment of hand osteoarthritis

AIMS

Radiographic imaging is essential in the diagnosis of hand osteoarthritis (HOA); however, it is unknown whether a multiplanar examination would add essential information to dorso-palmar (dp) views alone. This study evaluated whether an additional radiographic view would aid clinicians in the diagnostic process of HOA.

METHODS

The dp radiographs of both hands from 159 HOA patients were assessed according to the scores described by Kellgren and Lawrence (K/L). In oblique view images, structures similar to classic ostophytes (OPs) were found, namely bony proliferations on the dorsal and/or ventral margins of joints, and were documented as dorsal/ventral OPs (dvOPs). Function and pain were assessed by applying standardised read-out systems. Logistic regression analysis and Mann-Whitney tests were implemented.

RESULTS

The presence of dvOPs was associated with the degree of joint damage; however, dp views were sufficient to estimate radiographic changes. Only a few joints showed dvOPs as the only structural alteration; nevertheless, in almost all cases, classical radiographic OA changes were found in dp views of other joints of the same or the contralateral hand. The presence of dvOPs did not affect joint function or pain according to established scores, but was associated with radiographic progression in distal interphalangeal joints.

CONCLUSION

This is the first study to confirm that additional radiographic planes, oblique/lateral views, are not necessary in the diagnostic process in HOA in daily clinical practice. Nevertheless, the presence of dvOPs reflect more severe joint damage and is associated with radiographic progression in HOA; hence, oblique/lateral views could be a useful tool for academic purposes.

Diagnosis and Treatment of Genetic HFE-Hemochromatosis: The Danish Aspect

This paper outlines the Danish aspects of HFE-hemochromatosis, which is the most frequent genetic predisposition to iron overload in the five million ethnic Danes; more than 20,000 people are homozygous for the C282Y mutation and more than 500,000 people are compound heterozygous or heterozygous for the HFE-mutations. The disorder has a long preclinical stage with gradually increasing body iron overload and eventually 30% of men will develop clinically overt disease, presenting with symptoms of fatigue, arthralgias, reduced libido, erectile dysfunction, cardiac disease and diabetes. Subsequently the disease may progress into irreversible arthritis, liver cirrhosis, cardiomyopathy, pancreatic fibrosis and osteoporosis. The effective standard treatment is repeated phlebotomies, which in the preclinical and early clinical stages ensures a normal survival rate. Early detection of the genetic predisposition to the disorder is therefore important to reduce the overall burden of clinical disease. Population screening seems to be cost-effective and should be considered.

Ultrasound verified inflammation and structural damage in patients with hereditary haemochromatosis-related arthropathy

Background

Chronic arthropathy occurs in approximately two thirds of patients with hereditary haemochromatosis (HH). The aim was to study inflammatory and structural lesions in patients with HH with (HH-A) and without arthropathy (HH-WA) using ultrasonography.

Methods

This was a cross-sectional study of 26 patients with HH-A, 24 with HH-WA and 37 with hand osteoarthritis (HOA). Clinical examination was performed in 68 joints, and we retrieved data on hand function, pain and global disease activity (all using a visual analogue scale (VAS)), morning stiffness and ferritin levels. Standard x-ray and ultrasound were conducted in 36 joints (hands, hips, knees and ankles), and we graded grey scale synovitis (GSS), power Doppler ultrasound (PD), osteophytes, erosions, tenosynovitis and cartilage damage semi-quantitatively in accordance with prior publications.

Results

Ultrasound revealed a high proportion of inflammatory changes in HH-A; GSS was found in 96.2% and PD signals in 80.8% of patients (median GSS score 9, PD score 2.5). The frequency of these findings was similar in HOA. Inflammation was also common in HH-WA, yielding GSS in 83.3% and PD signals in 50.0% of patients. Cartilage damage was most prominent in HH-A as compared to HH-WA and HOA (median scores 11.0, 2.5 and 2.0, respectively). The prevalence and extent of erosions and osteophytes were similar in all groups. None of the ultrasound scores was associated with pain or function; GSS, PD, osteophyte and cartilage scores correlated with x-ray-verified structural damage.

Conclusion

A high prevalence of ultrasound-verified inflammation and cartilage damage was found in HH-A, and to a lesser extent in HH-WA. These findings were associated with x-ray-verified damage but not with clinical scores of pain and function.

Inflammatory bone spur formation in psoriatic arthritis is different from bone spur formation in hand osteoarthritis

OBJECTIVE

To investigate the different patterns of bone spur formation in psoriatic arthritis (PsA) and hand osteoarthritis (OA), using high-resolution peripheral quantitative computed tomography (QCT).

METHODS

The study group comprised 70 subjects (25 patients with PsA, 25 patients with hand OA, and 20 healthy controls). The 2 patient groups were similar with regard to age and sex distribution and clinical involvement of the metacarpophalangeal (MCP) joints. All patients underwent high-resolution peripheral QCT scanning of the second, third, and fourth MCP joints of the dominantly affected hand. Demographic and disease-specific data were recorded, and the number, size, and distribution of bone spurs were assessed and compared between patients with PsA and patients with hand OA.

RESULTS

The overall number and size of bone spurs were similar in patients with PsA and patients with hand OA. However, localization of lesions within individual joints was substantially different between patients with PsA and those with hand OA. In PsA, bone spurs dominated the radial sides of the joints (for the metacarpal head of the second joint, P < 0.001 versus hand OA; for the base of the second phalangeal joint, P < 0.001 versus hand OA), whereas the palmar and dorsal quadrants were the predilection sites in hand OA. Detailed anatomic analysis showed that bone spurs in the entheseal regions were prominent in patients with PsA but rare in patients with hand OA, and that bone spurs in patients with hand OA typically emerged at the cartilage-bone interphase and the joint margins.

CONCLUSION

Our findings show that the overall number and size of bone spurs are similar in patients with PsA and patients with hand OA. Nonetheless, the anatomic sites of bone proliferation are different between these 2 groups of patients.

HFE-related hemochromatosis: an update for the rheumatologist

Hereditary hemochromatosis is a frequent disease in Caucasian populations. It leads to progressive iron overload in a variety of organs. The most common cause is the C282Y homozygous mutation in the HFE gene. The classical triad of skin hyperpigmentation, diabetes, and liver cirrhosis is nowadays rare but musculoskeletal symptoms are common in HFE-related hemochromatosis. Typically the second and third metacarpophalangeal joints, and the wrist, hip, and ankle joints are affected. Clinical symptoms include osteoarthritis-like symptoms, pseudogout attacks, and synovitis sometimes resembling rheumatoid arthritis. Radiographs show degenerative changes with joint space narrowing, osteophytes, and subchondral cysts. Chondrocalcinosis in the wrist and knee joints is seen in up to 50 % of patients. Although most other organ manifestations regress during phlebotomy, musculoskeletal symptoms often persist or even become worse. Importantly, patients are at an increased risk of severe large-joint arthritis necessitating joint replacement surgery. Therefore, future research should focus on the pathogenesis and treatment options for HH arthropathy.

VCAM-1 serum levels are associated with arthropathy in hereditary haemochromatosis

OBJECTIVES

The aim of this study was to assess the role of vascular adhesion molecule 1 (VCAM-1) in patients with hereditary haemochromatosis (HH) with or without arthropathy.

METHODS

Sera from a large cross-sectional cohort of unselected HH patients (n=147) were obtained and compared to an age-matched and sex-matched control group. Serum levels of VCAM-1 were measured by ELISA and were correlated with clinical measures.

RESULTS

VCAM-1 serum levels were elevated in HH patients as compared to matched controls (mean 913±456 vs 654±451 ng/ml, p<0.0001). Within the HH patient group, VCAM-1 levels were much higher in patients with arthropathy and joint replacement surgery. VCAM-1 levels correlated well with radiographic measures of HH arthropathy (r=0.36, p<0.0001). Multivariate regression analysis confirmed a highly significant association of VCAM-1 serum levels and the presence of HH arthropathy, independent from diabetes, body mass index and age.

CONCLUSIONS

VCAM-1 serum levels emerge as a biomarker for haemochromatosis arthropathy.