Establishment of osteoblast culture from human ethmoidal sinus

Objective: Chronic sinusitis is characterized by persistent chronic inflammation of the sinus system and local expression and release of various cytokines, such as IL-1β, IL-4, IL-6, IL-8, TGF-β and TNF-α are deeply involved in the pathogenesis of the disease. We hypothesized that not only the sinus mucosa-containing cells, such as epithelial cells and fibroblasts, but also osteoblasts, of which sinus bone structure consists, may contribute to this inflammatory network. This study evaluates the development and establishment of an osteoblasts culture system derived from human ethmoidal sinus as an initial step toward verifying this hypothesis. Methods: Ethmoidal sinus bone was obtained from patients at the time of sinus surgery for chronic sinusitis and outgrowth cell sheets were obtained according to the explant-outgrowth cell culture technique. In order to examine the specific characteristics of osteoblasts in the obtained cells, four major features of osteoblasts (collagen type I, osteocalcin synthesis, alkaline phosphatase activity and extracellular matrix mineralization ability) were investigated at the third passage of the culture and productions of TGF-β1, which modulate osteoblast proliferation and maturation in an autocrine fashion, in the cultured medium was also investigated in time of culture up to 20 days. Results: The cells obtained in our study clearly show collagen type I synthesis, osteocalcin synthesis, alkaline phosphatase activity and production of visible extracellular matrix mineralization. Production of TGF-β1 in the medium did not significantly different in time of culture up to 20 days. Conclusion: Our results, the first of their kind, indicate that osteoblast-like cells can be cultured from adult human ethmoidal sinus bones. It suggested that proliferation and maturation of the osteoblast were continuously modulated in an autocrine fashion by producing TGF-β1.