The relationship between clinical phenotype and kallikrein-kinin bioregulation in different forms of arthritis.

OBJECTIVE: Patients with rheumatoid arthritis (RA) have shown increased levels of neutrophils generating kallikrein-kinin peptides in blood which are potent mediators of inflammation. This study investigated the association between the bioregulation of kinin-mediated inflammation with the clinical, quality of life, and imaging characteristics (e.g. ultrasonography) of different arthritides. METHODS: Patients with osteoarthritis (OA, n = 29), gout (n = 10) and RA (n = 8) were recruited and screened for clinical symptoms, quality of life, and ultrasonographical assessment of arthritis. Blood neutrophils were assessed for the expression of bradykinin receptors (B1R and B2R), kininogens and kallikreins by immunocytochemistry with visualization by bright field microscopy. Levels of plasma biomarkers were measured by ELISA and cytometric bead array. RESULTS: Quality of life (SF-36 domains and summary scores; including pain; and, HAQ) was similar across OA, gout and RA patients; with the exception of worse physical functioning scores between OA and gout patients. Synovial hypertrophy (on ultrasound) differed between groups (p = 0.001), and the dichotomised Power Doppler (PD) score of greater than or equal to 2 (PD-GE2) was marginally significant (p = 0.09). Plasma IL-8 were highest in patients with gout followed by RA and OA (both, P < 0.05). Patients with RA had higher plasma levels of sTNFR1, IL-1ß, IL-12p70, TNF and IL-6, compared to OA and gout patients (all, P < 0.05). Patients with OA had higher expression of K1B and KLK1 on blood neutrophils followed by RA and gout patients (both, P < 0.05). Bodily pain correlated with B1R expression on blood neutrophils (r = 0.334, p = 0.05), and inversely with plasma levels of CRP (r = -0.55), sTNFR1 (r = -0.352) and IL-6 (r = -0.422), all P < 0.05. Expression of B1R on blood neutrophils also correlated with Knee PD (r = 0.403) and PD-GE2 (r = 0.480), both P < 0.05. CONCLUSIONS: Pain levels and quality of life were similar between patients with OA, RA and gout with knee arthritis. Plasma inflammatory biomarkers and B1R expression on blood neutrophils correlated with pain. Targeting B1R to modulate the kinin-kallikrein system may pose as a new therapeutic target in the treatment of arthritis.

A systematic review of ultrasonography in gout and asymptomatic hyperuricaemia.

Gout is one of the most common inflammatory arthritides. The literature reveals that management of this condition is often suboptimal. Imaging techniques, such as ultrasound (US), may assist in the diagnosis and management of gout and asymptomatic hyperuricaemia (AH). To undertake a systematic review evaluating US as an outcome tool in gout and asymptomatic hyperuricaemia, articles published in Medline and PubMed (1975-February 2012) were identified. Data was extracted and categorised into four different groups namely tophi, articular cartilage, soft tissue pathologies and bony changes, with a focus on validity, responsiveness, reproducibility and feasibility. Lesions reported in the literature include tophi, cartilage abnormalities, soft tissue lesions and erosions. US is able to detect tophi, using MRI as the gold standard, and is sensitive to change. The double contour sign seen overlying cartilage is specific to gout and sensitive to change. Synovial pathology is identified in gout, with some reporting intrasynovial hyperechogeneicity is suggestive of gout. US was less sensitive than MRI to cortical erosions in gout, but better than conventional radiography. Interobserver reliability when assessed ranged from fair to substantial agreement for soft tissue changes and was very good for assessing tophi, double contour and erosions. US is a promising tool which could be used in the diagnosis and management of gout. More studies are needed to assess responsiveness, reliability and feasibility.