Tartrate-resistant acid phosphatase

About: Tartrate-resistant acid phosphatase is a research topic. Over the lifetime, 1115 publications have been published within this topic receiving 45937 citations. The topic is also known as: HPAP & SPENCDI.

Titanium IV ions induced human osteoclast differentiation and enhanced bone resorption in vitro

Abstract: There is increasing evidence that titanium (Ti) ions are released from orthopedic implants, with concentrations in the range of 1 microM in tissue and blood, and may play a role in aseptic loosening of orthopedic implants. This study investigated whether Ti(IV) ions induce differentiation of monocytic osteoclast precursors into osteo-resorptive multinucleated cells and influence the activation and function of in vitro generated osteoclasts. Human monocytes and in vitro generated osteoclasts were exposed to 1 microM Ti(IV) ions for 10 days. Thereafter, osteoclast differentiation, activation, and function were evaluated. Transcription of specific osteoclastic genes was measured using quantitative reverse transcription polymerase chain reactions, which showed increased expression of tartrate-resistant acid phosphatase (TRAP) in approximately 20% of Ti(IV)-treated monocytes. Detection and quantification of intracellular TRAP activity using ELF97 as a fluorescent substrate revealed a significant increase of TRAP-positive cells in Ti(IV)-treated monocytes. Additionally, as demonstrated on dentin slide cultures, Ti(IV)-treated monocytes became functional bone resorbing cells, significantly increasing their osteo-resorptive activity to similar levels as osteoclasts in vitro. These results suggest that Ti(IV) ions released by biocorrosion from orthopedic implants induce differentiation of monocytes toward mature, functional osteoclasts, which may well contribute the pathomechanism of aseptic loosening.

Zinc compounds inhibit osteoclast-like cell formation at the earlier stage of rat marrow culture but not osteoclast function

Abstract: The effect of zinc compounds on osteoclast-like cell formation in rat marrow culture in vitro was investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone resorbing hormone (1, 25-dihydroxyvitamin D3 and parathyroid hormone [1-34]). Osteoclast-like cell formation was estimated by staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of 1, 25-dihydroxyvitamin D3 (10(-8) M) or parathyroid hormone (PTH; 10(-8) M) induced a remarkable increase in osteoclast-like multinucleated cells (MNC). These increases were clearly inhibited by the presence of zinc sulfate or zinc-chelating dipeptide (beta-alanyl-L-histidinato zinc; AHZ) in the concentration range of 10(-7) to 10(-5) M. The inhibitory effect was seen at the earlier stage of osteoclast-like MNC formation. However, zinc compounds (10(-6) M) did not have an effect on PTH (10(-8) M)-induced osteoclast-like cell formation in the presence of EGTA (5 x 10(-4) M), dibucaine (10(-5) M) or staurosporine (10(-9) M). Moreover, when osteoclasts isolated from rat femoral-diaphyseal tissues were cultured for 24 h in the presence of zinc compounds (10(-7) to 10(-5) M), the compounds did not have an effect on cell numbers or lysosomal enzymes activity (acid phosphatase and beta-glucuronidase) in the cells. The present study clearly demonstrates that zinc compounds inhibit osteoclast-like cell formation at the earlier stage with differentiation of marrow cells.