Chlamydia trachomatis is present and metabolically active during the remitting phase in synovial tissues from patients with chronic Chlamydia-induced reactive arthritis

BACKGROUND

Patients with chronic Chlamydia-induced reactive arthritis (ReA) often show a remitting-relapsing disease phenotype. Some information regarding bacterial and host responses to one another during active disease is available but no information for quiescence. This article presents the first molecular genetic insight into the behavior of bacterium and host during remitting ReA.

METHODS

Synovial biopsies were procured from the knees of 4 patients with quiescent ReA by the Parker-Pearson technique. Nucleic acids prepared from them were analyzed by real-time polymerase chain reaction (PCR) and reverse transcription-PCR, and results were compared with data averaged from the knee synovial tissue samples of 10 patients with active ReA.

RESULTS

Real-time PCR indicated that bacterial load in remitting samples was approximately 20% of that in active disease samples. Transcripts from the p60-encoding gene were equal to or higher than those seen in active disease. Messenger RNAs (mRNAs) from the paralog p60-encoding genes were equal to or lower than those of active disease. Host mRNAs encoding interleukin-10, tumor necrosis factor-α and interferon-γ were 4-fold lower than those in active disease samples, whereas monocyte chemotactic protein 1 and regulated upon activation, normal t-cell expressed, and secreted mRNA levels were equal to or higher.

CONCLUSIONS

Bacterial load in synovial tissue of patients with remitting disease is lower than that of active disease, but mRNAs encoding proinflammatory proteins are equal to or higher than those of active disease. Transcription in the host is attenuated for cytokines and chemokines. These initial results demonstrate that organism is present and metabolically active in synovium during the remitting phase of chronic Chlamydia-induced ReA and that the genetic events characterizing quiescence are complex.

Pathologic finding of increased expression of interleukin-17 in the synovial tissue of rheumatoid arthritis patients

Rheumatoid arthritis (RA) is a common autoimmune disease of chronic systemic inflammatory disorder that will affect multiple tissues and organs such as skin, heart or lungs; but it principally attacks the joints, producing a nonsuppurative inflammatory and proliferative synovitis that often progresses to major damaging of articular cartilage and joint ankylosis. Although the definite etiology is still unknown, recent studies suggest that T-helper cells (Th17) may play a pivotal role in the pathogenesis of RA. And interleukin-17 (IL-17), which is a cytokine of Th17 cells, may be a key factor in the occurrence of RA. The binding of IL-17 to specific receptor results in the expression of fibroblasts, endothelial and epithelial cells and also synthesis of several major factors such as tumor necrosis factor alpha (TNF-α), IL-1β that result in the structural damage of RA joints. Though some previous studies have shown that IL-17 exists in the synovium of RA, few has definite proof quantitatively by pathology about its existence in synovial membrane. This study comprised of 30 RA patients and 10 healthy control, pathologic study of the synovial membrane showed increased expression of IL-17 in the synovial tissue of RA patients, the intensity is compatible with clinical severity of disease as validated by DAS28 score and disease duration. Northern blot study also confirmed the increased expression of IL-17 in the synovial tissues. This study sheds further light that IL-17 may be a key factor in the pathogenesis of RA and a determinant of disease severity.

Rapid musculoskeletal ultrasound for painful episodes in adult haemophilia patients

Little objective information exists about musculoskeletal bleeding patterns in haemophilic arthropathy. Bleeding is assumed to be the cause of painful joints or muscles. Clotting factor treatment is provided empirically, but often does not alleviate pain. We hypothesized that perception of pain aetiology is unreliable, and introduced point-of-care high-resolution musculoskeletal ultrasound (MSKUS) to differentiate intra-articular bleeds vs. joint inflammation, and intra-muscle bleeds vs. other regional pain syndromes. To assess painful musculoskeletal episodes in adult haemophiliacs, we used rapid MSKUS, employing grey scale and power Doppler examination. Forty episodes in 30 adult haemophiliacs were evaluated. Thirty three of the 40 episodes were patient-reported as 'bleeding', five as 'arthritis-type' pain and two as 'undecided'. Of the 33 bleeding reports, only 12 were confirmed by MSKUS; the other episodes revealed other pathology. In contrast, three of five perceived arthritis flares were reclassified as bleeds. Similarly, physician assessment was incorrect in 18 of 40 instances. Swelling and warmth were present in approximately half of confirmed bleeding and non-bleeding episodes, and therefore not useful clinically. Few of the painful episodes were symptom controlled at the time of MSKUS. Management changed based on objective imaging findings in >70% of episodes, which resulted in symptom improvement >60% of the time. Significant discrepancies exist between MSKUS findings and patient/physician-perceived pain classification as bleeding or other musculoskeletal symptoms. Current practice of prescribing clotting factor or conservative measures based on pain perception seems inadequate and suggests that point-of-care imaging should be included into modern haemophilia care.

Consecutive radiosynovectomy procedures at 6-monthly intervals behave independently in haemophilic synovitis

BACKGROUND

Previous studies on the same group of patients investigated here demonstrated the effectiveness of radiosynovectomy in the treatment of chronic haemophilic synovitis even if one, two or three radiosynovectomy procedures (RS-1, RS-2, RS-3) may be necessary. The purpose of this study was to determine whether the joints' response to each radiosynovectomy procedure behaved independently or not.

MATERIALS AND METHODS

One hundred and fifty-six radiosynovectomies were performed in 104 joints of 78 people diagnosed with chronic haemophilic synovitis. The patient's mean age was 18 years. Fifty-eight patients required radiosynovectomy in a single joint, whereas 20 received treatment in more than one joint. Of the 104 joints subjected to radiosynovectomy, 33 were elbows, 47 knees and 24 ankles. Radiosynovectomy was carried out with either yttrium-90 or rhenium-186 (1-3 injections with 6-month intervals between them). Of the 104 joints, 68 required a single injection of the radioisotope (RS-1), 20 required two injections (RS-2) and 16 required three injections (RS-3). In eight cases (7.6%), the affected joints eventually required surgery.

RESULTS

An analysis of seven variables (number of bleeding episodes, articular pain, range of motion in flexion and extension, muscle strength in flexion and extension, and synovial thickness by imaging) demonstrated that each consecutive radiosynovectomy behaves independently in haemophilic synovitis.

DISCUSSION

Each consecutive radiosynovectomy behaves independently in haemophilic synovitis. This finding had not been documented in the literature before the present study.

Peripatellar synovitis: comparison between non-contrast-enhanced and contrast-enhanced MRI and association with pain. The MOST study

PURPOSE

To assess the diagnostic performance of signal changes in Hoffa's fat pad (HFP) assessed on non-contrast-enhanced (CE) magnetic resonance imaging (MRI) in detecting synovitis, and the association of pain with signal changes in HFP on non-CE MRI and peripatellar synovial thickness on CE MRI.

METHODS

The Multicenter Osteoarthritis (MOST) Study is an observational study of individuals who have or are at high risk for knee OA. All subjects with available non-CE and CE MRIs were included. Signal changes in HFP were scored from 0 to 3 in two regions using non-CE MRI. Synovial thickness was scored from 0 to 2 on CE MRI in five peripatellar regions. Sensitivity, specificity and accuracy of HFP signal changes were calculated considering synovial thickness on CE MRI as the reference standard. We used logistic regression to assess the associations of HFP changes (non-CE MRI) and synovial thickness (CE MRI) with pain from walking up or down stairs, after adjusting for potential confounders.

RESULTS

A total of 393 subjects were included. Sensitivity of infrapatellar and intercondylar signal changes in HFP was high (71% and 88%), but specificity was low (55% and 30%). No significant associations were found between HFP changes on non-CE MRI and pain. Grade 2 synovial thickness assessed on CE MRI was significantly associated with pain after adjustments for potential confounders.

CONCLUSION

Signal changes in HFP detected on non-CE MRI are a sensitive but non-specific surrogate for the assessment of synovitis. CE MRI identifies associations with pain better than non-CE MRI.

The role of synovitis in osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis worldwide yet there is still a lack of effective treatments for this condition. Increasingly, attention has turned to the role of the synovium in OA as it is now recognized, in part from the use of modern imaging techniques, that synovitis is both common and associated with pain. This offers a target for treatment, for both symptom and potential structure modification. In this review we discuss the evidence for histological and imaging-detected synovitis and the current role of antisynovial therapies in OA.

Assessment of synovitis to predict bone erosions in rheumatoid arthritis

Although rheumatoid arthritis (RA) is traditionally considered as the prototype of destructive arthritis, the course of the disease varies considerably, with some patients experiencing more rapid progression of joint damage and disability than others. Given the increasing availability of treatment targets and options, timely recognition of individual's outcomes could allow therapeutic allocation according to personalized benefit-risk profiles. Research efforts are thus increasingly focused at discovering predictive markers that could identify patients with aggressive, rapidly progressive disease and poor prognosis. As joint destruction in RA is the result of the cumulative burden of inflammation, variables reflecting the severity of synovitis and its persistence over time might refine our ability to build early prognostic algorithms. The goal of this article is to review the clinical implications of the assessment of synovitis in relation to radiographic outcomes. Traditional and novel assessment tools will be discussed, including clinical measures, imaging techniques and tissue biomarkers. Achievements in the field of synovial tissue analysis and peripheral blood biomarkers of synovitis represent only the first steps of ongoing progress, which still need to be integrated into the phenotypic heterogeneity of RA.

Association of plasma n-6 and n-3 polyunsaturated fatty acids with synovitis in the knee: the MOST study

In osteoarthritis (OA) the synovium is often inflamed and inflammatory cytokines contribute to cartilage damage. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have anti-inflammatory effects whereas omega-6 polyunsaturated fatty acids (n-6 PUFAs) have, on balance, proinflammatory effects. The goal of our study was to assess the association of fasting plasma phospholipid n-6 and n-3 PUFAs with synovitis as measured by synovial thickening on contrast enhanced (CE) knee MRI and cartilage damage among subjects in the Multicenter Osteoarthritis Study (MOST). MOST is a cohort study of individuals who have or are at high risk of knee OA. An unselected subset of participants who volunteered obtained CE 1.5T MRI of one knee. Synovitis was scored in six compartments and a summary score was created. This subset also had fasting plasma, analyzed by gas chromatography for phospholipid fatty acid content, and non-CE MRI, read for cartilage morphology according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) method. The association between synovitis and cartilage morphology and plasma PUFAs was assessed using logistic regression after controlling for the effects of age, sex, and BMI. 472 out of 535 subjects with CE MRI had complete data on synovitis, cartilage morphology and plasma phospholipids. Mean age was 60 years, mean BMI 30, and 50% were women. We found an inverse relation between total n-3 PUFAs and the specific n-3, docosahexaenoic acid with patellofemoral cartilage loss, but not tibiofemoral cartilage loss or synovitis. A positive association was observed between the n-6 PUFA, arachidonic acid, and synovitis. In conclusion, systemic levels of n-3 and n-6 PUFAs which are influenced by diet, may be related to selected structural findings in knees with or at risk of OA. Future studies manipulating the systemic levels of these fatty acids may be warranted to determine the effects on structural damage in knee OA.

Synovitis in spondyloarthritides

Recent studies using magnetic resonance imaging have suggested that the subchondral bone marrow and the entheses are the sites which are primarily involved in the peripheral and axial inflammation found in patients with spondyloarthritides. Histopathological analyses indicated that the typical morphological features at these sites reflect an inflammation (osteitis) at the bone cartilage interface and in the subchondral bone marrow. This finding implies that synovitis may be of minor importance, especially in comparison to other inflammatory joint diseases such as rheumatoid arthritis. Here, we summarize current available knowledge on synovial involvement in inflammatory processes related to SpA.

Synovitis in psoriatic arthritis: immunohistochemistry, comparisons with rheumatoid arthritis, and effects of therapy

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy associated with psoriasis that affects the peripheral joints, spine, and entheses. Most patients with PsA present with peripheral synovitis of the oligoarticular or polyarticular subtype. As one of the targets of this disease, studies on the synovium may provide insight into the mechanisms involved in this condition. Key findings from the available studies comparing synovial tissue of PsA and rheumatoid arthritis patients are discussed in this review. Also, changes in the synovial infiltrate, expression of proinflammatory cytokines and adhesion molecules, and vascularity in synovial tissue after treatment with various medications are addressed. Finally, a model for proof-of-principle study design using serial synovial biopsies is described, which could be used to predict clinical (in)efficacy in early clinical trial design in PsA.

Cartilage oligomeric matrix protein - inflammation biomarker in knee osteoarthritis

Chondrocytes and synovial cells synthesize Cartilage Oligomeric Matrix Protein (COMP) when activated by proinflammatory cytokines. The aim of this study was to analyze and compare ultrasound parameters of joint inflammation, effusion and synovitis with the levels of COMP in the serum of patients with primary osteoarthritis. Ultrasound was done and the concentration of COMP (ng/mL was examined in 88 patients. 75% of patients had effusion (size 10.13±4.35 mm), 62.5% had effusion in lateral recessus (LR), 28.4% (size 8.53±2.27 mm) in suprapatelar (SR), and 27.3% (size 11.38±4.44 mm) in medial (MR). 67% of patients had synovitis size 4.84±3.57 mm in SR, 3.15±1.86 mm in MR; and 6.09±2.80 mm in LR. 17.0% of patients had nodular type of synovitis, 30.7% had diffusive, and 19.3% nodular - diffusive. There was a significant link between the size of synovitis and effusion in SR (r = 0.966, p = 0.000), MR (r = 0.812, p = 0.009) and LR (r = 0.886, p = 0.003). The median of COMP concentration was 54 (44.5-58) ng/mL in patients without effusion. In those with effusion it was 57 (48.75-64.25) ng/mL (p = 0.030). Without synovitis it was 52 (45.5-58) ng/mL, with synovitis 58 (50-66) ng/mL, (p = 0.006), diffusion type synovitis 60 (50-67) ng/mL, nodular 57 (50-62) ng/mL, nodular-diffusion 54 (44.5-66.5) ng/mL (p = 0.014). With longer osteophytes the median of COMP was 56 (48-64) ng/mL, with shorter osteophytes 55 (46.5-59) ng/mL (p = 0.000). Cartilage oligomeric matrix protein has a moderate significance in the assessment of disturbance of the metabolism of synovial and cartilage tissue in patients with knee osteoarthritis (sensitivity = 59%; specificity = 50%; cut off = 53.5 ng/mL).

Differing effects of exogenous and endogenous hydrogen sulphide in carrageenan-induced knee joint synovitis in the rat

BACKGROUND AND PURPOSE

Recent findings suggest that the noxious gas H(2)S is produced endogenously, and that physiological concentrations of H(2)S are able to modulate pain and inflammation in rodents. This study was undertaken to evaluate the ability of endogenous and exogenous H(2)S to modulate carrageenan-induced synovitis in the rat knee.

EXPERIMENTAL APPROACH

Synovitis was induced in Wistar rats by intra-articular injection of carrageenan into the knee joint. Sixty minutes prior to carrageenan injection, the rats were pretreated with indomethacin, an inhibitor of H(2)S formation (DL-propargylglycine) or an H(2)S donor [Lawesson's reagent (LR)].

KEY RESULTS

Injection of carrageenan evoked knee inflammation, pain as characterized by impaired gait, secondary tactile allodynia of the ipsilateral hindpaw, joint swelling, histological changes, inflammatory cell infiltration, increased synovial myeloperoxidase, protein nitrotyrosine residues, inducible NOS (iNOS) activity and NO production. Pretreatment with LR or indomethacin significantly attenuated the pain responses, and all the inflammatory and biochemical changes, except for the increased iNOS activity, NO production and 3-NT. Propargylglycine pretreatment potentiated synovial iNOS activity (and NO production), and enhanced macrophage infiltration, but had no effect on other inflammatory parameters.

CONCLUSIONS AND IMPLICATIONS

Whereas exogenous H(2)S delivered to the knee joint can produce a significant anti-inflammatory and anti-nociceptive effect, locally produced H(2)S exerts little immunomodulatory effect. These data further support the development and use of H(2)S donors as potential alternatives (or complementary therapies) to the available anti-inflammatory compounds used for treatment of joint inflammation or relief of its symptoms.

SAPHO Syndrome Diagnosis and Treatment: Report of Five Cases and Review of the Literature

Background:

The term “SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis) syndrome” includes a variety of musculoskeletal disorders associated with skin conditions; Osteitis is the most prominent skeletal lesion, whereas palmoplantar pustulosis and acne are the main skin lesions. Diagnosing SAPHO syndrome is difficult, because this syndrome is often confused with suppurative osteomyelitis, which has similar clinical and pathologic findings. SAPHO diagnosis is even more difficult when atypical sites are involved and there are no skin lesions.

Patients and Methods:

This case series presents five patients (3 women, 2 men), ages 27 to 44 years, who came to the Orthopaedic Department outpatient clinic for evaluation of pain in the humerus, clavicle, sacroiliac joints, and/or distal radius, and were diagnosed with SAPHO syndrome. Clinical and radiologic findings, treatment and outcome data, with up to 4 years of follow-up are presented. An extensive discussion of the clinical presentation, published literature, treatment options and outcome of SAPHO syndrome is also included.

Results:

Once the diagnosis of SAPHO syndrome was established, treatment with antibiotics (clindamycin) and non steroid anti-inflammatory drugs (lornoxicam) was remarkably effective. All patients did well and remained symptom free for up to four years, after a 3-8 month course of treatment.

Interpretation:

SAPHO syndrome should be included in the differential diagnosis when evaluating patients with lytic, sclerotic, or hyperostotic bone lesions and pain. Prompt SAPHO syndrome recognition, followed by appropriate therapy with antibiotics and NSAIDs can produce rapid symptom resolution, while avoiding unnecessary procedures and longterm antibiotic therapy.

Water-soluble fullerene (C60) inhibits the development of arthritis in the rat model of arthritis

Recently, it has been demonstrated that oxygen free radicals have an important role as a signaling messenger in the development of inflammation and osteoclastogenesis, suggesting the implication of oxygen free radicals in the pathogenesis of arthritis. The aim of this study was to examine the potential of a strong free-radical scavenger, water-soluble fullerene (C60), as a protective agent against synovitis in arthritis, both in vitro and in vivo. In the presence or absence of C60 (0.1, 1.0, 10.0 μM), human synovial fibroblasts, synovial infiltrating lymphocytes or macrophages were incubated with tumor necrosis factor-α (TNF-α) (10.0 ng/mL), and the production of proinflammatory cytokines by the individual cells were analyzed. C60 significantly suppressed the TNF-α-induced production of proinflammatory cytokines in synovial fibroblasts, synovial infiltrating lymphocytes and macrophages in vitro. Adjuvant induced arthritic rats were used as an animal model of arthritis. Rats were divided into two subgroups: control and treatment with C60 at 10.0 μM. The left ankle joint was injected intraarticularly with water-soluble C60 (20 μl) in the C60-treated group, while, as a control, the left ankle joint in the control rats received phosphate-buffered saline (20 μl), once weekly for eight weeks. Ankle joint tissues were prepared for histological analysis. In adjuvant-induced arthritic rats, intra-articular treatment with C60 in vivo reduced synovitis and alleviated bone resorption and destruction in the joints, while control ankle joints showed progression of synovitis and joint destruction with time. These findings indicate that C60 is a potential therapeutic agent for inhibition of arthritis.

Treatment of diffuse pigmented villonodular synovitis of the knee with combined surgical and radiosynovectomy

Treatment of extensive diffuse pigmented villonodular synovitis (PVNS) of large joints by isolated surgical resection is unsatisfactory, with high rates of local recurrence. Post-synovectomy adjuvant treatment with external beam radiation therapy or intra-articular injection of radioactive material as yttrium-90 ((90)Y) yielded better results. Between January 2005 and January 2007, 12 patients (eight men and four women aged 19-49 years) with extensive diffuse PVNS of the knee were treated. All patients had an adjuvant post-operative external beam radiation therapy (2,600-3,000 cGy) conventionally fractionated 200 cGy/fraction, five fractions/week, 6-8 weeks after surgery. Mean follow-up time was 27 months (range from 20 to 36 months). All patients were followed up using clinical assessment, magnetic resonance imaging, and plain X-ray. In all patients, neither evidence of disease recurrence nor progression of bone or articular destruction was noted. No complications were noticed after surgery or after post-operative external beam radiation therapy. A combination of debulking surgery using anterior and posterior approach with adjuvant post-operative external beam radiation therapy for extensive diffuse PVNS of the knee joint is a reliable treatment method, with good results in regard to the incidence of local recurrence and functional outcome.

The tumour suppressor gene p53 modulates the severity of antigen-induced arthritis and the systemic immune response

p53 is a transcription factor with a well-described role in the induction of apoptosis and cell cycle arrest as part of a protective response to a variety of stressful stimuli. Expansion of inflamed tissue in rheumatoid arthritis has been related to the loss of functioning p53, and the severity of collagen-induced arthritis is increased in p53-/- mice. Our objective was to assess the role of p53 in a model of adaptive immunity, antigen-induced arthritis (AIA). AIA was induced in p53-/- and wild-type mice by priming with methylated bovine serum albumin followed by intra-articular challenge. Severity of arthritis was assessed using a standardized scoring system and synovial apoptosis was detected by TdT-mediated biotin-dUTP nick-end labelling. Splenocyte proliferation was measured by [H(3)] incorporation and interferon (IFN)-gamma release. Splenocyte viability was assessed using Titreglow. Splenic T cell activation status was assessed by flow cytometry. Serum cytokines were measured using enzyme-linked immunosorbent assay. Increased severity of AIA in p53-/- mice was associated with decreased synovial apoptosis and with increased delayed-type hypersensitivity response, increased mitogen and antigen-induced splenocyte proliferation and increased IFN-gamma release in p53-/- mice compared with wild-type mice. Antigen-specific immunoglobulin responses were equivalent in both groups. Splenocyte viability was increased in p53-/- mice but T cell apoptosis was equivalent. T cell activation markers were increased in p53-/- mice compared with wild-type mice. Lipopolysaccharide-induced tumour necrosis factor release was increased in p53-/- mice with a trend to increased interleukin-6 in p53-/- mice compared with littermates. p53 is involved in the modulation of adaptive and innate immune responses relevant to arthritis models and is also involved in the modulation of severity of AIA by both cell-cycle dependent and cell-cycle-independent mechanisms.

Ultrasound of the small joints of the hands and feet: current status

The aim of this article was to review the current status of ultrasound imaging of patients with rheumatological disorders of the hands and feet. Ultrasound machines with high-resolution surface probes are readily available in most radiology departments and can be used to address important clinical questions posed by the rheumatologist and sports and rehabilitation physician. There is increasing evidence that ultrasound detects synovitis that is silent to clinical examination. Detection and classification of synovitis and the early detection of bone erosions are important in clinical decision making. Ultrasound has many advantages over other imaging techniques with which it is compared, particularly magnetic resonance. The ability to carry out a rapid assessment of many widely spaced joints, coupled with clinical correlation, the ability to move and stress musculoskeletal structures and the use of ultrasound to guide therapy accurately are principal amongst these. The use of colour flow Doppler studies provides a measure of neovascularisation within the synovial lining of joints and tendons, and within tendons themselves, that is not available with other imaging techniques. Disadvantages compared to MRI include small field of view, poor image presentation, and difficulty in demonstrating cartilage and deep joints in their entirety. Contrast-enhanced magnetic resonance provides a better measure of capillary permeability and extracellular fluid than does ultrasound. The ability to image simultaneously multiple small joints in the hands and feet and their enhancement characteristics cannot be matched with ultrasound, though future developments in 3-D ultrasound may narrow this gap. Magnetic resonance provides a more uniform and reproducible image for long-term follow-up studies.

Treating very early rheumatoid arthritis

Rheumatoid arthritis (RA) is common and leads to joint damage due to persistent synovitis. The persistence of inflammation is maintained by hyperplastic stromal tissue, which drives the accumulation of leukocytes in the synovium. Aggressive treatment after the first 3-4 months of symptoms, with either disease modifying anti-rheumatic drugs or anti-tumor necrosis factor (TNF)-alpha therapy, reduces the rate of disease progression. However, it rarely switches off disease such that remission can be maintained without the continued need for immunosuppressive therapy. There is increasing evidence that the first few months after symptom onset represent a pathologically distinct phase of disease. This very early phase may translate into a therapeutic window of opportunity during which it may be possible to permanently switch off the disease process. The rationale for, and approaches to, treatment within this very early window are discussed.

Magnetic resonance imaging: opportunities for rheumatoid arthritis disease assessment and monitoring long-term treatment outcomes

Early diagnosis of rheumatoid arthritis (RA) combined with early initiation of an appropriate treatment regimen is acknowledged as an important factor in improving clinical outcomes in patients with RA. Early diagnosis allows treatment intervention to occur sooner in order to inhibit the progression of structural joint damage as well as providing improved patient quality of life. Unfortunately, early diagnosis has been challenging due to the non-specific signs and symptoms associated with many polyarthropathies and the lack of accurate definitive diagnostic tests that can accurately classify RA at presentation. The emphasis on early diagnosis has fueled the need for powerful, sensitive, non-invasive imaging techniques that not only accurately define RA and give an indication of prognosis, but can also serve as a tool to monitor long-term treatment outcomes. This article reviews the potential uses of magnetic resonance imaging as a tool for the classification, documentation, and clinical monitoring of RA.

Association of MHC and rheumatoid arthritis. HLA polymorphisms in phenotypic variants of rheumatoid arthritis

Genes in the human leukocyte antigen (HLA) region remain the most powerful disease risk genes in rheumatoid arthritis (RA). Several allelic variants of HLA-DRB1 genes have been associated with RA, supporting a role for T-cell receptor-HLA-antigen interactions in the pathologic process. Disease-associated HLA-DRB1 alleles are similar but not identical and certain allelic variants are preferentially enriched in patient populations with defined clinical characteristics. Also, a gene dosing effect of HLA-DRB1 alleles has been suggested by the accumulation of patients with two RA-associated alleles, especially in patient subsets with a severe disease course. Therefore, polymorphisms in HLA genes are being explored as tools to dissect the clinical heterogeneity of the rheumatoid syndrome. Besides HLA polymorphisms, other risk genes will be helpful in defining genotypic profiles correlating with disease phenotypes. One such phenotype is the type of synovial lesion generated by the patient. HLA genes in conjunction with other genetic determinants may predispose patients to a certain pathway of synovial inflammation. Also, patients may or may not develop extraarticular manifestations, which are critical in determining morbidity and mortality. HLA genes, complemented by other RA risk genes, are likely involved in shaping the T-cell repertoire, including the emergence of an unusual T-cell population characterized by the potential of vascular injury, such as seen in extraarticular RA.

Model studies directed toward the application of boron neutron capture therapy to rheumatoid arthritis: boron delivery by liposomes in rat collagen-induced arthritis

The application of boron neutron capture therapy to rheumatoid arthritis requires the selective delivery of the boron-10 isotope to the synovitic tissue. The use of liposomes as a boron delivery method has been explored through the measurement of the time course biodistribution of boron in rats with collagen-induced arthritis (CIA). Small unilamellar vesicles were composed of a 1:1 mixture of distearoylphosphatidylcholine and cholesterol, incorporated K[nido-7-CH3(CH2)15-7,8-C2B9H11] as an addend in the lipid bilayer and encapsulated Na3[a2-B20H17NH2CH2CH2NH2] in the aqueous core. The tissue concentration of boron delivered by liposomes was determined by inductively coupled plasma-atomic emission spectroscopy after intravenous injection of liposome suspensions into Louvain rats with CIA. With the low injected doses of boron used [13-18 mg of boron per kg (body weight)], the peak boron concentration observed in arthritic synovium was 29 microg of boron per g of tissue. The highest synovium/blood boron ratio observed was 3.0, when the synovial boron concentration was 22 microg of boron per g of tissue. In an attempt to increase the synovium/blood boron ratio by lowering the blood boron concentration, a liposomal formulation characterized by a shorter blood clearance time was examined. Thus, the biodistribution of liposomes with additional K[nido-7-CH3(CH2)15-7, 8-C2B9H11] incorporated in the vesicle membrane not only demonstrated more rapid blood clearance and slightly higher synovium/blood boron ratios but also exhibited reduced boron uptake in synovial tissue. These studies with boron neutron capture therapy for CIA suggest that this form of therapy may be feasible in the treatment of rheumatoid arthritis.

Light and electron microscopic investigation of equine synovial membrane. A comparison between healthy joints and joints with intraarticular fractures and osteochondrosis dissecans

Light and electron microscopic examination was made on equine synovial membrane from 23 healthy joints, nine joints with synovitis caused by intraarticular fracture and 10 joints with synovitis caused by osteochondrosis dissecans. Histologically as well as ultrastructurally the equine synovial membrane from healthy joints was of principally the same character as described in other species. Three types of synovial membrane — areolar, fibrous and adipose — and two types of lining cell were distinguished histologically. Ultrastructurally three types of lining cells were distinguished: A and Β type and an intermediate cell type. In healthy joints they were loosely arranged, parallel to the joint surface in an intercellular matrix, which was in direct continuity with the joint space. In joints with intraarticular fracture there was mild inflammation of the synovial membrane. There was elongation and hyperplasia of the lining cells with a relative increase in type A cells. The cell surface of lining cells was increased through filopodia. There was also an increase in cytoplasmic organelles i.e. hyperplasia of rough endoplasmic reticulum and Golgi complexes in Β type cells and an increase in lysosomes, and increased numbers of vesicles of varying types in A cells. In joints with osteochondrosis dissecans the lining cell hyperplasia and the inflammation in the synovial membrane were more prominent. Ultrastructurally the same alterations as in the previous group were seen including a relative increase in the number of A cells but degenerative changes were common in the lining cells. These changes were dilatation and vesiculation of rough endoplasmic reticulum, mitochondrial condensation, dilatation of the nuclear envelope and loss of plasma membranes, leading to disintegration of cells.