title: Zeolite A increases proliferation, differentiation, and transforming growth factor beta production in normal adult human osteoblast-like cells in vitro.
abstract: Silicon in trace amounts enhances bone formation, and the silicon-containing compound zeolite A (ZA) increases eggshell thickness in hens. In the studies reported here, treatment of nearly homogeneous strains of normal human osteoblast-like cells for 48 h with ZA at 0.1-100 micrograms/ml induced a dose-dependent increase (r = 0.35, P < 0.001) in DNA synthesis (n = 31) to 162 +/- 16% (mean +/- SEM) of control and in the proportion of cells in mitosis (n = 4) from 9.1 +/- 1.8 to 27.0 +/- 4.5% (r = 0.69, P < 0.005). ZA treatment also increased alkaline phosphatase activity (P < 0.05) and osteocalcin release (P < 0.05) but did not significantly affect collagen production per individual cell. The mitogenic action of ZA was dependent on cell seeding density over the range of 1250-40,000 cells per cm2, which is consistent with induction of an autocrine factor(s). TGF-beta is a potent mitogen for osteoblasts. ZA treatment increased the steady-state mRNA levels of transforming growth factor beta 1 (TGF-beta 1) and induced the release of the latent form of TGF-beta protein into the conditioned medium within 6 h. We conclude that ZA induces the proliferation and differentiation of cells of the osteoblast lineage.
authors.affiliation: Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota.
authors.forename: P E
authors.initials: PE
authors.lastname: Keeting
authors.forename: M J
authors.initials: MJ
authors.lastname: Oursler
authors.forename: K E
authors.initials: KE
authors.lastname: Wiegand
authors.forename: S K
authors.initials: SK
authors.lastname: Bonde
authors.forename: T C
authors.initials: TC
authors.lastname: Spelsberg
authors.forename: B L
authors.initials: BL
authors.lastname: Riggs
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000538:Aluminum Silicates / Q000494:pharmacology*; D015152:Blotting, Northern; D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D006801:Humans; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D012044:Regression Analysis; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000494:pharmacology; D017641:Zeolites
chemical_list: D000538:Aluminum Silicates; D016212:Transforming Growth Factor beta; D015675:Osteocalcin; D017641:Zeolites; D003094:Collagen; D004247:DNA; D000469:Alkaline Phosphatase; D002117:Calcitriol