A model of chronic enthesitis and new bone formation characterized by multimodal imaging

Entheseal Involvement in Spondyloarthritis (SpA) and Gout: An Ultrasound Comparative Study

Objective

To compare the assessment of entheses in subjects with spondyloarthritis (SpA) with patients with gout by the Madrid Sonographic Enthesis Index (MASEI).

Method

This cross-sectional study includes videos of entheses evaluated by ultrasound (US) of 30 patients with SpA diagnosed according to the ASAS criteria and 30 patients with gout established by the presence of monosodium urate crystals. Entheses were evaluated for MASEI in 2 Institutes located in two different countries. Demographic and clinical data were registered. Total MASEI score, MASEI-inflammatory, and MASEI-chronic damage were analyzed. Comparisons between groups were obtained by chi-square test and Student's t-test. An inter-reading US reliability was realized.

Results

Patients with gout were older and had significantly more comorbidities than those with SpA. The total MASEI score was not significantly different among diseases (p = 0.07). MASEI-inflammatory was significantly more prevalent at the Achilles tendon in SpA, while the proximal patellar tendon was in gout. Power Doppler was higher in SpA compared to gout (p = 0.005). MASEI-chronic damage related to calcification/enthesophytes predominated in gout (p = 0.043), while calcaneal erosions did in SpA (p = 0.008). The inter-reader concordance was excellent (0.93, CI 95% 0.87–0.96, p = 0.001).

Conclusions

SpA and gout similarly involve entheses according to MASE, however, some inflammatory and chronic lesions differ significantly depending on the underlying disease and tendon scanned.

The complement system drives local inflammatory tissue priming by metabolic reprogramming of synovial fibroblasts

Arthritis typically involves recurrence and progressive worsening at specific predilection sites, but the checkpoints between remission and persistence remain unknown. Here, we defined the molecular and cellular mechanisms of this inflammation-mediated tissue priming. Re-exposure to inflammatory stimuli caused aggravated arthritis in rodent models. Tissue priming developed locally and independently of adaptive immunity. Repeatedly stimulated primed synovial fibroblasts (SFs) exhibited enhanced metabolic activity inducing functional changes with intensified migration, invasiveness and osteoclastogenesis. Meanwhile, human SF from patients with established arthritis displayed a similar primed phenotype. Transcriptomic and epigenomic analyses as well as genetic and pharmacological targeting demonstrated that inflammatory tissue priming relies on intracellular complement C3- and C3a receptor-activation and downstream mammalian target of rapamycin- and hypoxia-inducible factor 1α-mediated metabolic SF invigoration that prevents activation-induced senescence, enhances NLRP3 inflammasome activity, and in consequence sensitizes tissue for inflammation. Our study suggests possibilities for therapeutic intervention abrogating tissue priming without immunosuppression.

Enthesitis in psoriatic arthritis (Part 1): pathophysiology

Enthesitis is a key manifestation of PsA and current knowledge supports the concept that it may be among the primary events in the development of this disease, as well as other forms of SpA. Patients with PsA seem to have a different threshold to mechanical stress, which may be genetically determined. Hence patients with psoriatic disease respond pathologically with inflammation after being exposed to physiological mechanical stress. Activation of pro-inflammatory mediators such as IL-17 and TNF-α as well as the influx of innate immune cells are key events in the development of enthesitis in PsA. Chronic entheseal inflammation is accompanied by new bone formation, leading to bony spurs in peripheral (entheseophytes) and axial (syndesmophytes) structures. This article reviews the current knowledge on the mechanisms involved in the development of enthesitis in patients with PsA.

Quantitative T2 mapping-based tendon healing is related to the clinical outcomes during the first year after arthroscopic rotator cuff repair

PURPOSE

The objective of this study was to determine the correlation between quantitative T2 mapping-based tendon healing and clinical outcomes during the first year after arthroscopic rotator cuff repair.

METHODS

Twenty-two patients with rotator cuff tear were prospectively recruited. Serial clinical and MRI follow-up assessments were carried out at 1 month, 6 months and 12 months after surgery. Twenty healthy volunteers were involved and were examined with clinical and MRI assessments. Clinical assessments included Constant Score (CS), the American Shoulder and Elbow Surgeons (ASES), the modified University of California, Los Angles (UCLA) scores and Visual Analog Scale (VAS). The region of interest of tendon healing was defined directly over the medial suture anchor on T2 mapping. Spearman correlation coefficient was used to analyze the correlations between MRI measurements and clinical outcomes.

RESULTS

All clinical scores indicated significant improvements over the postoperative observation period compared with the initial preoperative values (all P < 0.001). At 12 months, all of the patients returned to their daily life activities. The T2 values of the healing site significantly decreased over time (P < 0.001) and were comparable to those of healthy tendons at 12 months (n.s.). Additionally, the T2 values were negatively correlated with CS (r = - 0.5, P < 0.001), ASES (r = - 0.5, P < 0.001), and UCLA (r = - 0.5, P < 0.001); and positively correlated with VAS score (r = 0.4, P < 0.001). No significant correlations were found between Sugaya classification and clinical scores (all n.s.).

CONCLUSIONS

With regard to tendon healing during the first follow-up year, the T2 values of the healing site decreased with the improvement of clinical outcomes over time.

LEVEL OF EVIDENCE

II.

Tendon and ligament mechanical loading in the pathogenesis of inflammatory arthritis

Mechanical loading is an important factor in musculoskeletal health and disease. Tendons and ligaments require physiological levels of mechanical loading to develop and maintain their tissue architecture, a process that is achieved at the cellular level through mechanotransduction-mediated fine tuning of the extracellular matrix by tendon and ligament stromal cells. Pathological levels of force represent a biological (mechanical) stress that elicits an immune system-mediated tissue repair pathway in tendons and ligaments. The biomechanics and mechanobiology of tendons and ligaments form the basis for understanding how such tissues sense and respond to mechanical force, and the anatomical extent of several mechanical stress-related disorders in tendons and ligaments overlaps with that of chronic inflammatory arthritis in joints. The role of mechanical stress in 'overuse' injuries, such as tendinopathy, has long been known, but mechanical stress is now also emerging as a possible trigger for some forms of chronic inflammatory arthritis, including spondyloarthritis and rheumatoid arthritis. Thus, seemingly diverse diseases of the musculoskeletal system might have similar mechanisms of immunopathogenesis owing to conserved responses to mechanical stress.

Effects of Conventional Uric Acid-Lowering Therapy on Monosodium Urate Crystal Deposits

OBJECTIVE

Few studies have systematically and quantitatively addressed the impact of urate-lowering therapy on monosodium urate (MSU) deposits. This study was undertaken to analyze the effect of lifestyle measures and conventional urate-lowering therapy on MSU deposits in patients with gout.

METHODS

In this prospective study, subjects with gout according to the American College of Rheumatology/European League Against Rheumatism classification criteria and presence of MSU deposits seen on dual-energy computed tomography (DECT) scans received either lifestyle intervention or conventional urate-lowering therapy for a mean period of 18 months before a follow-up DECT scan. Detected MSU deposits were quantified by volumetric measurement and validated by semiquantitative scoring, and baseline and follow-up measurements were compared.

RESULTS

Baseline and follow-up DECT scans were available for all 83 subjects. Six subjects discontinued treatment, and 77 subjects underwent a lifestyle intervention (n = 24) or were treated with allopurinol (n = 29), febuxostat (n = 22), or benzbromarone (n = 2) over the entire observation period. The mean serum uric acid (UA) level decreased from 7.2 to 5.8 mg/dl in the overall population. In patients who discontinued treatment, no change in MSU deposits or serum UA levels was observed. The burden of MSU deposits significantly decreased in patients undergoing lifestyle intervention (MSU volume P = 0.007; MSU score P = 0.001), and in patients treated with allopurinol (MSU volume and score P < 0.001) or febuxostat (MSU volume P < 0.001; MSU score P = 0.001). No significant decline in MSU deposits was noted in patients who discontinued treatment.

CONCLUSION

These data show that lifestyle intervention and xanthine oxidase inhibitors significantly decrease the MSU deposit burden. Hence, conventional gout therapy not only lowers serum UA levels, but also reduces pathologic MSU deposits.