Human neutrophils at inflammatory sites may be an important source of the chemotactic cytokines macrophage inflammatory protein 1 alpha (M1P-1 alpha; a C-C chemokine) and interleukin 8 (IL-8; a C-X-C chemokine). In this study, we show that the inflammatory microcrystals monosodium urate monohydrate (MSU) and calcium pyrophosphate dihydrate (CPPD), the major mediators of gout and pseudogout, dif...

Recruitment of various stem and progenitor cells is crucial for the regeneration of an injured organ. Levels of uric acid, one of the prototypical "alarm signals," surge after ischemia-reperfusion injury. Exogenous uric acid rapidly mobilizes endothelial progenitor cells and hematopoietic stem cells and protects the kidney from ischemia. The relatively fast responses to uric acid suggest that p...

OBJECTIVE To determine the reliability of a delay in the microscopic examination of synovial fluid (SF) to detect and identify crystals. METHODS Ninety one SF samples were examined, 31 with monosodium urate (MSU) crystals, 30 with crystals of calcium pyrophosphate dihydrate (CPPD), and 30 containing no crystals. The specimens were stored with EDTA, sodium heparin, and without anticoagulant at...

Monosodium urate (MSU) crystals are among the most potent pro-inflammatory stimuli and an innate immune inflammatory response to the crystal surface is intimately involved in the pathology of gouty arthritis. The responses of human neutrophils to MSU crystals represent an integral part of this innate response and a key component of the acute inflammatory response associated with gout. A signifi...

BACKGROUND Identification of monosodium urate (MSU) and calcium pyrophosphate dehydrate (CPPD) crystals in synovial fluid samples is diagnostic of gout and CPPD crystal related arthropathy. Various studies have shown poor consistency in results of crystal analysis. OBJECTIVE To determine whether training of the analysts increases the consistency. METHODS An expert rheumatologist gave a cour...

BACKGROUND Gout is an inflammatory disease that is caused by the increased production of Interleukin-1β (IL-1β) stimulated by monosodium urate (MSU) crystals. However, some hyperuricemia patients, even gouty patients with tophi in the joints, never experience gout attack, which indicates that pathogenic pathways other than MSU participate in the secretion of IL-1β in the pathogenesis of acute g...

Gout is the most prevalent inflammatory arthropathy. It displays a striking predilection to affect the first metatarsophalangeal joint (1 MTPJ) as well as joints within the mid-foot and ankle. The propensity of gout for the foot was recognised by the ancient Greeks who named it podagra, literally “foot-grabber”. A number of mechanisms have been proposed to explain this clinical observation. Hyp...

BACKGROUND MicroRNAs (miRNAs) serve as important regulators of inflammatory and immune responses and are implicated in several immune disorders including gouty arthritis. The expression of miR-146a is upregulated in the peripheral blood mononuclear cells of patients with inter-critical gout when compared to normouricemic and hyperuricemic controls and those patients with acute gout flares. Howe...

INTRODUCTION The murine air pouch is a bursa-like space that resembles the human synovial membrane. Injection of monosodium urate (MSU) crystals into the pouch elicits an acute inflammatory response similar to human gout. We conducted the present study to identify mRNAs that were highly regulated by MSU crystals in the pouch membrane. METHODS Air pouch membranes were meticulously dissected aw...