IL-1β, TNF-α, TGF-β, and bFGF expression in bone biopsies before and after parathyroidectomy

IL-1β, TNF-α, TGF-β, and b FGF expression in bone biopsies before and after parathyroidectomy.BackgroundThere is growing evidence pointing to an involvement of cytokines and growth factors in renal osteodystrophy. In this study, the expression of interleukin-lβ (IL-1β), tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), and basic fibroblast growth factor (bFGF) in bone biopsies taken from uremic patients before and 1 year after parathyroidectomy (PTX) was evaluated. Biochemical features and histomorphometric outcome were also studied.MethodsIliac bone biopsies were taken before and 1 year after PTX in nine uremic patients with severe hyperparathyroidism (HPT). Immunohistochemical techniques were used to identify the expression of IL-1β, TNF-α, TGF-β, and bFGF in these bone samples.ResultsAt the time of the second bone biopsy, the mean serum total alkaline phosphatase activity was normal, whereas mean serum intact parathyroid hormone (iPTH) level was slightly above the upper limit of normal values. Histomorphometric analysis showed a decrease in resorption parameters and static bone formation parameters after PTX. Dynamically, mineral apposition rate (MAR) and mineralization surface (MS/BS) decreased significantly. There was a marked local expression of IL-1β, TNF-α, TGF-β, and bFGF in bone biopsies before PTX, particularly in fibrous tissue and resorption areas. One year after PTX, IL-1β decreased from 23.6 ± 7.5% to 9.9 ± 3.1%, TNF-α from 4.5 ± 1.5% to 0.7 ± 0.8%, TGF-β from 49.6 ± 9.8% to 15.2 ± 4.6%, and bFGF from 50.9 ± 12.7% to 12.9 ± 7.9% (P < 0.001). A significant correlation was documented between cytokines and growth factors expression in bone with iPTH levels before and after PTX (P < 0.05).ConclusionsBased on these results, we suggest that IL-1β, TNF-α, TGF-β, and bFGF are involved in bone remodeling regulation, acting as local effectors, possibly under the control of PTH