acid-phosphatase and tibolone

An open study was carried out to evaluate changes in bone remodeling markers such as N-telopeptide (NTx), tartrate-resistant acid phosphatase (TRAP), total alkaline phosphatase (TAP), and bone alkaline phosphatase (BAP) during a 1-year continuous tibolone treatment in postmenopausal women.. Thirty-six postmenopausal women were recruited for receiving tibolone 2.5 mg per day for 1 year. Densitometry and determination of biochemical markers of bone metabolism in serum and urine were performed at 1, 3, 6, and 12 months.. Comparing baseline with 12 month's values, BAP and all resorption markers decreased significantly. NTx began to decrease since the initiation of the treatment (baseline: 74.4 +/- 5.3; 1 month: 57.5 +/- 4.2; 12 months: 36.6 +/- 2.8). BAP increased at the first month (baseline: 37.3 +/- 2.1; 1 month: 42.6 +/- 3.0) but diminished in the following months (12 months: 23.1 +/- 1.5). TAP started to decrease significantly only after 6 months of treatment (baseline: 37.3 +/- 2.1; 12 months: 31.4 +/- 2.3) and TRAP after 3 months (baseline: 9.8 +/- 0.4; 6 months: 9.1 +/- 0.5; 12 months: 8.2 +/- 0.4). Normal bone mineral density at distal and ultradistal forearm was maintained during the 1-year treatment (baseline: 0.42 +/- 0.01; 12 months: 0.42 +/- 0.01 and baseline: 0.33 +/- 0.01; 12 months: 0.33 +/- 0.01, respectively).. The use of tibolone 2.5 mg per day diminished progressively and significantly bone resorption and formation markers during 1-year treatment period.

Topics: Acid Phosphatase; Alkaline Phosphatase; Anabolic Agents; Biomarkers; Bone Density; Bone Remodeling; Collagen; Collagen Type I; Drug Administration Schedule; Female; Forearm; Humans; Isoenzymes; Middle Aged; Norpregnenes; Osteoporosis, Postmenopausal; Peptides; Tartrate-Resistant Acid Phosphatase

The effects of estrogen suppression on osteonal remodeling in young women was investigated using transiliac biopsies (eight paired biopsies + four single pre; three single post biopsies) taken before and after treatment for endometriosis (6 months) with analogs of gonadotrophin releasing hormone (GnRH). Estrogen withdrawal increased the proportion of Haversian canals with an eroded surface (106%, p = 0.047), a double label (238%, p = 0.004), osteoid (71%, p = 0.002), and alkaline phosphatase (ALP) 116%, p = 0.043) but not those showing tartrate-resistant acid phosphatase (TRAP) activity (p = 0.25) or a single label (p = 0.30). Estrogen withdrawal increased TRAP activity in individual osteoclasts in canals with diameters greater than 50 microns (p = 0.0089) and also the number of osteons with diameters over 250 microns (p = 0.049). ALP activity in individual osteoblasts was increased but not significantly following treatment (p = 0.051). Wall thickness was significantly correlated with osteon diameter (p < 0.001). In a separate group of patients (four pairs + one post biopsy) on concurrent treatment with tibolone, there was no significant increase in the osteon density, cortical porosity, median canal diameter, or the markers of bone formation and resorption. Enzyme activities and numbers of active canals were also not increased with the concurrent treatment, but there was still an increase in the osteon diameter. As previously shown for cancellous bone, estrogen withdrawal increased cortical bone turnover. We have now shown that resorption depth within Haversian systems was also increased with treatment. The enhanced TRAP activity in individual osteoclasts supports the concept that osteoclasts are more active following estrogen withdrawal in agreement with theoretical arguments advanced previously. Understanding the cellular and biochemical mechanisms responsible for increased depth of osteoclast resorption when estrogen is withdrawn may allow the development of new strategies for preventing postmenopausal bone loss.

Topics: Acid Phosphatase; Alkaline Phosphatase; Biomarkers; Biopsy; Bone Density; Bone Remodeling; Drug Therapy, Combination; Endometriosis; Estrogen Antagonists; Female; Gonadotropin-Releasing Hormone; Goserelin; Humans; Ilium; Isoenzymes; Norpregnenes; Osteoclasts; Osteoporosis, Postmenopausal; Software; Tartrate-Resistant Acid Phosphatase; Triptorelin Pamoate