Rheumatoid Arthritis: Boileau C

Avouac J, Uzan G, Kahan A, Boileau C, Allanore Y. · Rheumatology A department, René Descartes University, Cochin Hospital, APHP, 27 rue du faubourg Saint-Jacques, 75014 Paris, France. · Joint Bone Spine. · Pubmed #18314371 No free full text.

Abstract: In human adults, new blood vessels may form via endothelial sprouting from pre-existing endothelial cells/angioblasts (angiogenesis) or via the recruitment of circulating endothelial progenitor cells (EPCs) (vasculogenesis). EPCs are a population of bone marrow-derived cells able to differentiate into mature endothelial cells and participating in the formation of new blood vessels. The molecular phenotype of EPCs and processes leading to their mobilization from bone marrow and homing to neovascularization sites remain unclear. There is still debate regarding methods for their quantification and isolation. In the field of rheumatology, EPCs have been studied in multiple myeloma and inflammatory rheumatic disorders. In myeloma, data suggest that EPCs could be reliable biomarkers of tumor angiogenesis, growth and antiangiogenic therapy efficacy. Recent studies suggest that EPCs are involved in synovial vascularization, and may contribute to the increased cardiovascular morbidity and mortality in rheumatoid arthritis, known features of this disease. In systemic lupus erythematosus, preliminary data suggest that EPCs are decreased. Results available in systemic sclerosis are consistent with the hypothesis that EPCs are recruited during active disease; however, their levels may be depleted as the disease progresses and under chronic ischemic conditions. EPCs are important in vasculogenesis, and may be involved in other systemic features of inflammatory rheumatic disorders.

Wipff J, Allanore Y, Kahan A, Meyer O, Mouthon L, Guillevin L, Pierlot C, Glikmans E, Bardin T, Boileau C, Cornélis F, Dieudé P. · Rheumatology A Department, Cochin Hospital, Paris, France. · Ann Rheum Dis. · Pubmed #16464986 No free full text.

Abstract: The minor allele of the R620W missense single-nucleotide polymorphism (SNP; rs2476601) in the PTPN22 (protein tyrosine phosphatase non-receptor 22) gene has been reported to be associated with multiple autoimmune diseases, including type 1 diabetes, systemic lupus erythematosus, rheumatoid arthritis, juvenile idiopathic arthritis, autoimmune thyroiditis and vitiligo. Systemic sclerosis (SSc) is a connective tissue disease with some autoimmune abnormalities. The aim of our study was to test for association of the PTPN22*620W allele with SSc in a French Caucasian cohort with a case-control study of 121 patients with SSc and 103 controls. All patients and controls were genotyped for the PTPN22*R620W SNP. No association was found between the PTPN22*620W allele and SSc (7% v 9.2%, p = 0.39). The frequency of genotypes carrying at least one 620W allele was similar in both groups (13% v 17%, p = 0.38). The PTPN22*620W allele was also not associated with autoantibody patterns. Thus, the PTPN22*R620W polymorphism cannot be regarded as a genetic susceptibility factor for SSc in the French Caucasian population.

Pacquelet S, Presle N, Boileau C, Dumond H, Netter P, Martel-Pelletier J, Pelletier JP, Terlain B, Jouzeau JY. · Faculté de Médecine, Vandoeuvre-lès-Nancy, France. · J Rheumatol. · Pubmed #12465160 No free full text.

Abstract: OBJECTIVE: To compare the potency of 2 cytokines, interleukin 17 (IL-17) and IL-1beta, on rat cartilage proteoglycan synthesis with special attention to nitric oxide (NO) and peroxynitrite formation. METHODS: Chondrocytes in alginate beads were stimulated with human recombinant (rh) IL-17 (0.03 to 300.0 ng/ml) and/or rhIL-1beta (0.25 to 25.0 ng/ml) in the presence or not of L-NMMA or CuDips. Alternatively, rats were injected with either IL-17 (10.0 micro g) or IL-1beta (1.0 micro g) into each knee joint. NO concentrations were determined by a spectrofluorimetric assay, proteoglycan synthesis by 35SO4-2 incorporation, peroxynitrite generation by immunostaining for 3-nitrotyrosine, and IL-1beta mRNA expression by reverse transcription-polymerase chain reaction. RESULTS: IL-17 inhibited proteoglycan synthesis and increased NO production, both in vitro and in vivo, without inducing expression of IL-1beta mRNA in cartilage. Additive effects were observed when IL-17 was combined with low concentrations of IL-1. Surprisingly, a similar NO synthesis between IL-1 and IL-17 led to a less suppressive effect of IL-17 on cartilage anabolism than with IL-1. Both in vitro and in vivo, peroxynitrite formation was extensive with IL-1beta, but negligible or nonexistent with IL-17. L-NMMA and CuDips completely corrected the suppressive effect of IL-1beta on proteoglycan synthesis, unlike with IL-17. CONCLUSION: These data showed that NO is weakly involved in the IL-17 mediated inhibition of proteoglycan synthesis in rat. NO overload may not be predictive of any inhibitory effect on cartilage anabolism, but instead superoxide is a key regulator of NO contribution to chondrocyte dysfunction. Since IL-17 is a NO-producing cytokine with additive effects when combined with IL-1, it may play a pivotal role in cartilage destruction during rheumatoid arthritis, for which infiltrating cells produce high levels of superoxide and proinflammatory cytokines.