bFGF-Induced Alterations in Cellular Markers of Senescence in Growth-rescued Fibroblasts from Chronic Venous Ulcer and Venous Reflux Patients

Fibroblasts cultured from the distal lower extremity of chronic venous insufficiency (CVI) patients exhibit characteristics of cellular senescence. Basic fibroblast growth factor (bFGF) has been shown to improve growth rates in these fibroblasts. In bFGF-treated fibroblasts, levels of fibronectin and matrix metaloproteinase-2 (MMP-2), known to be up-regulated in senescence, were examined to determine whether bFGF induces changes in these markers of senescence with rescue of cellular proliferation. Fibroblasts were isolated from the distal leg of patients with CVI with and without ulcers (fb-D). In all patients, a control was obtained from the proximal ipsilateral thigh (fb-P). Cells were plated at 3000 cells/plate and treated with bFGF (20 ng/mL) on days 1, 5, 8, and 11. Total cell number was obtained on days 5 and 12 using the Coulter particle counter, and concurrently cells were plated at 10,000 cells/plate and treated with bFGF on the same schedule; cell lysate was harvested on day 12 for immunoblot analysis for MMP-2 and fibronectin. In all patients (n = 7), fb-P grew faster than fb-D (p = 0.039). fb-D showed a mean 3.3-fold increase in growth in response to bFGF, and immunoblot analysis demonstrated an up-regulation of fibronectin and MMP-2 in response to bFGF. This represents the possibility that by stimulating growth, bFGF may drive cells toward senescence. This suggests clinical implication for the use of bFGF and other growth factors in general.