Serum Tartrate-Resistant Acid Phosphatase 5b, but not 5a, Correlates with Other Markers of Bone Turnover and Bone Mineral Density

Abstract

Human serum contains two isoforms of tartrate-resistant acid phosphatase (TRACP) known as TRACP 5a and TRACP 5b with pH optima of 5.0 and 5.8, respectively. Preliminary data suggest that serum TRACP 5b is derived from osteoclasts and serum TRACP 5a from some other cells. It has been reported that heparin inhibits TRACP 5a but has no effect on the activity of TRACP 5b. Here we show that heparin has no effect on serum TRACP activity, as determined using our previously published immunoassay, suggesting that the immunoassay does not detect TRACP 5a. The change of serum TRACP 5b activity after 6 months HRT, determined by this immunoassay, correlated significantly with the changes of all markers of bone turnover determined, including serum N- and C-terminal propeptides of type I collagen and urinary-free deoxypyridinoline. Serum TRACP 5b activity was significantly elevated in patients with osteoporosis and had a significant negative correlation with bone mineral density (BMD). Serum TRACP 5a activity, determined by an immunoassay, showed no correlation with serum TRACP 5b activity, with BMD, or with any of the markers of bone turnover. These results show that serum TRACP 5b, but not 5a, reflects the bone resorption rate, and that our TRACP 5b immunoassay may be a specific method for the determination of the bone resorption rate from serum samples.

Suitability of Tartrate-Resistant Acid Phosphatase Type 5b as a Screening Marker for Bone Mineral Density in Community-Dwelling Elderly Individuals

“…Human TRAP has two subtypes, TRAP-5a and TRAP-5b (Halleen et al 2002). TRAP-5a contains sialic acid, which is not found in TRAP-5b.…”

“…TRAP-5a contains sialic acid, which is not found in TRAP-5b. Halleen et al (2000Halleen et al ( , 2002 developed TRAP with optimally purified antigenic properties and pH from human osteoclasts, which was identical to TRAP-5b and completely different from TRAP-5a, suggesting that TRAP-5b is derived from osteoclasts and TRAP-5a from other, unidentified sources, probably activated macrophages (Halleen et al Abbreviations as in Table 1. β: Standardized regression coefficient CI: Confidence interval Table 4.…”

“…Serum TRAP-5b activity has a low diurnal variability, its level is not affected by feeding, and it does not accumulate in the circulation in cases of renal or hepatic failure, so that the serum samples may be collected at any time of the day (Hallen et al 2000(Hallen et al , 2002Ohashi et al 2007;Nishizawa et al 2008;Qin et al 2008). Previous studies have shown that activity of serum TRAP-5b was significantly elevated in patients with osteoporosis and had a significant negative correlation with BMD (Halleen et al 2002;Qin et al 2008). Ohashi et al (2007) reported that postmenopausal women had higher TRAP-5b concentrations than premenopausal women, but no significant differences among age groups were found in healthy men.…”

In vitro osteoclastogenesis on textile chitosan scaffold

“…For microscopic analyses the chitosan fibres were tightened between the plastic rings of Minusheet ® -Holders (inner diameter 10 mm) (Minucells, Bad Abbach, Germany). Stand-alone scaffolds (diameter 10 mm) for quantitative biochemical analyses were processed by using the crown knot technique, which merges two chitosan fibres to form a circular threedimensional construct (Heinemann et al, 2008).…”

“…Coating with a thin layer of fibrillar collagen type I was applied to make the surface of the scaffolds biocompatible. The excellent suitability of textile chitosan fibre scaffolds for application in bone tissue engineering was demonstrated by cell culture experiments using a murine cell line of osteoblast-like cells (7F2) and human bone marrow stromal cells (hBMSC) (Heinemann et al, 2008;Heinemann et al, 2009). Both cell types revealed fast cell attachment, increase of the cell number over the cultivation period of 28 days, and the expression of the osteogenic phenotype as indicated by the typical pattern of ALP activity, osteocalcin immunostaining, and matrix mineralization.…”