Increased plasma levels of matrix metalloproteinase-9 are associated with the severity of chronic urticaria.

BACKGROUND: Matrix metalloproteinase (MMP)-9 is produced by many inflammatory cells such as macrophages, neutrophils, mast cells, eosinophils and T lymphocytes. Activated T cells are capable, through cell-cell contact, of inducing MMP-9 expression in human mast cells. OBJECTIVE: To investigate the activation status of peripheral CD4+ T cells and the level of MMP-9 in the plasma of patients with chronic urticaria (CU), and whether MMP-9 levels are in association with CU severity. METHODS: Study subjects included 29 patients with CU and 30 healthy control subjects. At the time of assessment, patients were divided into subgroups according to urticarial severity. Plasma levels of total MMP-9 (free pro-MMP-9 and free MMP-9) were determined by ELISA. CD4+ lymphocytes were positively selected with magnetic microbeads. After 48 h of activation, CD4+ T cells were assayed for both nuclear factor-kappa B (NF-kappa B) expression and proliferation. RESULTS: Plasma levels of MMP-9 were found to be significantly higher in 29 CU patients compared with 18 healthy controls (186 +/- 174 vs. 31 +/- 21 ng/mL, P<0.0001). We also found a significant correlation between MMP-9 levels and urticarial severity (r = 0.92, P<0.001). In addition, CD4+ T cells from CU patients expressed higher levels of NF-kappa B than CD4+ T cells from healthy controls (82 +/- 30 vs. 69 +/- 20 optical density, P = 0.007). Finally, as compared with seven healthy individuals, DNA synthesis in CD4+ T cells from seven CU patients was found to be significantly elevated (1000 +/- 240 vs. 751 +/- 166 counts per minute, P = 0.01). CONCLUSION: Increased levels of MMP-9 are found in CU patients, and particularly among those with severe disease. We also demonstrated that CD4+ T cells from such patients are highly activated.

The association of serum matrix metalloproteinases and their tissue inhibitor levels with scleroderma disease severity.

OBJECTIVE: Matrix metalloproteinase 3 (MMP-3) is reported to play an important role in the pathogenesis of systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Studies have also investigated the association of different tissue inhibitors of MMPs (TIMPs) with fibrosis in scleroderma (SSc). The aim of this study was to evaluate the correlation of serum MMP-1, 3 and TIMP-1 with severity and disease specific markers of SSc and RA. METHODS: Serum MMP-1,3 and TIMP-1 were measured in 42 SSc patients (age range 28-68 yr mean 47 yr) and compared to 29 RA and 30 healthy age- and sex-matched individuals. Elevated values of MMPs and TIMP-1 were defined as those greater than 2 SD above the normal mean. All SSc and RA patients were scored for disease severity. RESULTS: Serum MMP-1 was significantly elevated in 8/42 (19%) SSc patients (p = 0.01) but only in 2/29 (7%) RA patients (p = 0.2). Whereas MMP-3 levels were elevated in 10/29 (34%) RA patients (p = 0.002), it was elevated in only 5/42 (12%) SSc patients (p = 0.03). TIMP-1 was found elevated in 17/42 (40%) SSc patients (p = 0.001) and in only 4/29 RA patients (with a strong trend towards significance, p = 0.052). We found a significant association between the elevation of both MMPs and TIMP-1 levels, with the severity of SSc. Those who had an increase of more than one MMP and/or TIMP, demonstrated life-threatening major organ involvement such as end stage lung fibrosis, GI aperislasis, and severe cardiacfailure. Contrary to that in SSc, the severity of RA showed some trend of association with MMP-3 only. CONCLUSION: We confirm previous observations that MMPs and TIMPs may play an important role in various rheumatic diseases. Whereas serum increase of MMP-3 correlated with RA severity, SSc severity was more characterized by the increase of both MMP-1 and TIMP-1. This suggests that the MMPs and TIMPs involved in SSc are different than those playing a role in RA, which may indicate that in SSc they are produced in different locations than in RA.

The effect of osmotic and mechanical pressures on water partitioning in articular cartilage.

X-ray diffraction measurements on native and proteoglycan-free articular cartilage have been made in order to test the dependence of the lateral packing of the collagen molecules on the osmotic pressure gradient, either naturally occurring or externally applied, between the intra- and extrafibrillar compartments. From the information on collagen packing we have been able to calculate, albeit with several assumptions, the amount of intrafibrillar water as a function of pressure. In parallel with the above measurements, we have quantitated, using serum albumin partitioning, the intrafibrillar water in proteoglycan-free cartilage, as a function of mechanically applied pressure. The results of both sets of experiments lead to the conclusion that the molecular packing density, and hence the intrafibrillar water content, are a function of the osmotic pressure difference between the extrafibrillar and intrafibrillar spaces or the equivalent mechanically applied pressure. The determination of intrafibrillar water has enabled us to calculate, from measured values of fixed charge density, the internal osmotic pressure of cartilage specimens, both in compressed and uncompressed states.

Some biochemical and biophysical parameters for the study of the pathogenesis of osteoarthritis: a comparison between the processes of ageing and degeneration in human hip cartilage.

We have investigated the changes in some of the biochemical and biophysical properties of human femoral head cartilage on the one hand during ageing and on the other hand in osteoarthritis. Topographical variations were also investigated. The parameters studied were those relevant to cartilage function, viz., proteoglycan concentration (as expressed by the concentration of negatively charged groups), the rate of glycosaminoglycan synthesis, water content, osmotic pressure and fluid loss during compression. During ageing the fixed charge density was found to increase at all sites of the femoral head provided fibrillation was absent: osmotic pressure increased accordingly whilst loss of fluid under the effect of externally applied compression diminished. In cartilage from osteoarthritic joints the opposite changes were found. The rate of GAG synthesis varied considerably with site on the femoral head. It decreased somewhat with age on the superior surface, but increased on the inferior surface. When the same sites were compared, the rate of GAG synthesis in cartilage from osteoarthritic heads was either the same as or lower than in cartilage form normal heads in the same group.