Combined effects of infliximab and methotrexate on rheumatoid arthritis osteoblastic cell metabolism.

The goal of this study is to investigate the in vitro effects of two disease-modifying anti-rheumatic drugs, largely used in the treatment of rheumatoid arthritis (RA), [infliximab (IFX) and methotrexate (MTX)], in RA primary osteoblast cell cultures. MTX inhibited proliferation and metabolic activity in RA osteoblasts was able to increase apoptosis. Conversely, IFX increased the proliferation, osteocalcin production and the alkaline phosphatase activity. Interestingly, IFX appeared to antagonise the negative effect exerted by MTX. Both drugs significantly reduced the IL-6 production in osteoblasts when used alone, and the combination of the two agents resulted in a significant additional reduction of IL-6 synthesis, with an apparent additive effect. The present study suggests that MTX exerts negative direct effects on bone metabolism in RA patients, but the combined treatment with anti-TNF-α can be beneficial for the interaction of MTX with bone cells.

RANKL/OPG ratio and DKK-1 expression in primary osteoblastic cultures from osteoarthritic and osteoporotic subjects.

OBJECTIVE: To evaluate the expression of Dickkopf-1 protein factor (DKK-1), DKK-2, and ß-catenin, components of the Wnt pathway, in human osteoarthritic (OA) and osteoporotic (OP) osteoblasts and to correlate it to cell metabolic activity, proliferation, and receptor activator of nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) expression. METHODS: Primary human osteoblast cultures were obtained from healthy, OA, and OP donors. In each cell population we evaluated DKK-1, DKK-2, nonphosphorylated ß-catenin and RANKL/OPG expression, osteocalcin and alkaline phosphatase (ALP) synthesis, and cell proliferation, both in basal condition and after vitamin D3 stimulation. RESULTS: DKK-1 and DKK-2 showed opposite patterns of expression in OA and OP osteoblasts. The RANKL/OPG ratio was significantly higher in the OP group because of a greater expression of RANKL, whereas it was significantly lower in the OA group because of a higher expression of OPG. Treatment with vitamin D3 increased the RANKL/OPG ratio and DKK-2 expression and reduced DKK-1 expression in each cell population, but did not affect ß-catenin levels. Both osteocalcin and ALP production and cell proliferation were enhanced in OA cells and reduced in the OP ones. CONCLUSION: These data confirm that OA and OP are characterized by opposite bone changes, consisting of reduced bone remodeling processes with increased osteoblast activity in OA, and enhanced bone resorptive activity with reduction of osteoblast metabolism in OP, and suggest that the Wnt pathway is involved in the pathogenesis of both diseases.

In vitro and in vivo angiogenic activity of osteoarthritic and osteoporotic osteoblasts is modulated by VEGF and vitamin D3 treatment.

Vascular Endothelial Growth Factor (VEGF) is a potent angiogenic factor, which also regulates bone remodeling. Osteoblasts not only respond to VEGF stimulation, but also express and synthesize this factor. The present study was aimed to evaluate in vitro differences in VEGF production and expression of cultured human osteoblastic cells derived from healthy donors and from subjects affected by osteoarthritis and osteoporosis, under basal conditions than after vitamin D3, and to investigate the angiogenic activity of culture media obtained by these cells in chick embryo chorioallantoic membrane (CAM) assay. The results showed that normal and pathological osteoblasts produce and express VEGF and 1,25 dihydroxy-vitamin D3 treatment increases protein and m-RNA VEGF levels. In addition culture media of pathological osteoblasts induce a strong angiogenic response, greater than observed with culture medium of normal cells, suggesting the involvement of osteoblast-derived VEGF in the pathogenesis of bone diseases.

Nailfold capillaroscopic findings in systemic sclerosis related lung fibrosis and in idiopathic lung fibrosis.

OBJECTIVE: Interstitial lung diseases (ILDs) are heterogeneous pathological conditions, which can be idiopathic or associated to other diseases, such as connective tissue diseases (CTD), especially systemic sclersosis (SSc). Both in primary and secondary forms of ILDs, fibroblastic and vascular anomalies are involved in the progressive structural destruction of lung parenchyma. Nailfold video-capillaroscopy (NFC) is a non-invasive diagnostic tool that permits detection of the main local microvascular alterations in SSc, which are an expression of the systemic vascular changes characteristic of this disease. The aim of this study is to record the range of capillaroscopic anomalies in patients with idiopathic pulmonary fibrosis (IPF) and to detect the main differences compared to patients with pulmonary fibrosis associated to SSc (SSc-PF). METHODS: We performed NFC on 23 patients with PF secondary to systemic sclerosis (SSc-PF), 20 patients with IPF, and 22 patients with chronic obstructive pulmonary disease (COPD) and we analysed the differences in morphological capillaroscopic parameters between the study groups. RESULTS: The main finding of this study was the detection of minor capillaroscopic alterations in patients affected by IPF compared to SSc-PF patients, the latter having typical capillary loop changes. Particularly, we found that in IPF patients capillary density was significantly reduced and neoangiogenic aspects was significantly greater compared to patients with COPD. CONCLUSIONS: An altered nailfold capillaroscopic pattern in IPF, as observed in this study, seems to support the hypothesis that a systemic vascular dysfunction in these patients plays a role in the pathogenesis of the disease.