Search

Objectives. SSc (scleroderma) is an often fatal disease characterized by widespread tissue fibrosis. Fibroblasts play a key role in SSc-associated fibrosis. This study was designed to determine: (i) whether fibroblasts isolated from skin of patients with SSc have increased lysophosphatidic acid-activated Cl - current (ICI LPA ) activity vs healthy controls; (ii) whether myofibroblast differentiation is involved in SSc skin fibrosis; and (iii) whether SSc fibroblasts have different proliferation rates vs controls. Methods. Skin biopsies were taken from involved and uninvolved skin of SSc patients and controls. Whole-cell perforated patch-clamping was used to measure ICI LPA activity in fibroblasts isolated and cultured from these biopsies. Western blotting was used to measure α-smooth muscle actin (α-SMA). Proliferation was measured using a colorimetric assay. Results. Fibroblasts cultured from SSc skin show significantly increased ICI LPA activity following LPA exposure compared with control skin fibroblasts. α-SMA protein was significantly increased in cultured SSc skin fibroblasts vs controls. No significant differences in proliferation rates were found. Conclusions. Elevated ICI LPA activity is a hallmark of SSc skin fibroblasts. Blocking ICI LPA activation may be a new therapeutic approach for treating SSc-associated fibrosis.

Summary A single infusion of pamidronate was given to patients with systemic sclerosis (scleroderma, SSc) to assess effects on cytokine production by peripheral blood mononuclear cells (PBMC) and lymphocyte subsets. Eighteen patients with SSc received a single intravenous dose of 60 mg of pamidronate and were followed for 6 months. Assessment of cytokine production [interferon (IFN)-γ, interleukin (IL)-10, transforming growth factor (TGF)-β1, tumour necrosis factor (TNF)-α and IL-4] by PBMC and lymphocyte subsets by flow cytometry was carried out before and after the pamidronate infusion. Unstimulated PBMC produced increased amounts of IFN-γ and TNF-α and reduced levels of TGF-β1 for up to 24 weeks after the infusion. γδ T cells from patients with SSc were activated in vitro and produced increased IFN-γ. The effects of pamidronate on modulation of cytokine profiles in patients with SSc may merit future study.