Serum Bone Gla Protein Levels Research Articles

Platelet-rich plasma promotes bone formation, restrains adipogenesis and accelerates vascularization to relieve steroids-induced osteonecrosis of the femoral head

Steroid-associated necrosis of the femoral head (SANFH) is one of the most common and refractory chronic diseases with increasing incidence. The typical pathological changes of SANFH include decreased osteogenic differentiation, enhanced intramedullary adipocytes deposition and impaired osseous circulation. In this study, we investigated the effects and potential mechanisms of Platelet-rich plasma (PRP) on SANFH. Sixty Sprague-Dawley rats were randomly divided into the control, PRP donor, model, and PRP groups. Compared to the model group, PRP treatment significantly increased the hemorheological indexes and serum levels of bone gla-protein (BGP) and vascular endothelial growth factor (VEGF), while decreased the levels of triglyceride (TG) and total cholesterol (TC). Meanwhile, Micro-CT and histopathological stain (Hematoxylin-eosin and Alcian blue-hematoxylin/orange G staining) were performed on the femoral head for morphological and histopathological evaluation, indicating that bone trabecular microstructure and bone mineral density (BMD) were significantly improved after PRP treatment. Immunohistochemical analysis revealed that PRP remarkably up-regulated the expression of osteogenic markers including β-catenin and alkaline phosphatase (ALP), angiogenic markers containing VEGF and platelet endothelial cell adhesion molecule-1 (CD31), while down-regulated adipogenic markers involving fatty acid-binding protein (FABP-4), and peroxisome proliferator-activated receptor gamma (PPAR-γ) in SANFH rat models. In summary, for the first time, PRP was demonstrated to prevent the development of SANFH through stimulating bone formation and vascularization as well as retarding adipogenesis.

Electroacupuncture stimulation at CV4 prevents ovariectomy-induced osteoporosis in rats via Wnt-β-catenin signaling.

The present study aimed to investigate the effect of electroacupuncture stimulation at CV4 (also termed Guanyuan) on femoral osteocalcin also termed bone gla protein (BGP), alkaline phosphatase (ALP), bone mineral density (BMD) and biomechanics, as well as the Wnt-β-catenin signaling pathway in rats with postmenopausal osteoporosis. Female Sprague-Dawley rats (4.5-months old) were randomly divided into sham, Ovx, CV4 and mock groups (n=10/group). With the exception of those in the sham group, the rats were ovariectomized to induce postmenopausal osteoporosis. The rats in the CV4 and mock groups were given electroacupuncture at CV4 and non-acupoint, respectively. The rats in the Ovx model and sham groups underwent identical fixing procedures, but did not undergo electroacupuncture. Following treatment, hematoxylin and eosin staining was used to observe morphological changes in the left femoral trabecular bone, and a three-point-bending test was used to analyze femur biomechanics and determine the BMD. In addition, an enzyme-linked immunosorbent assay was used to measure the serum levels of ALP/BGP and reverse transcription-quantitative polymerase chain reaction was used detect the expression levels of Wnt3a, β-catenin and Runx2. In the present study, it was demonstrated that electroacupuncture at CV4 significantly improved the osteoporotic morphological changes that occurred in the ovariectomized rats, increased serum ALP and BGP levels, enhanced the maximum and fracture loads, increased BMD (P<0.01), and activated the Wnt-β-catenin signaling pathway. These findings demonstrated that electroacupuncture stimulation at CV4 affected bone formation and promoted bone metabolism in rats with postmenopausal osteoporosis, possibly by activating the Wnt-β-catenin signaling pathway.

The Effects of Exenatide Microsphere on Serum BGP and ALP Levels in ZDF Rats after Implantation

The aim of this project is to investigate the impact of diabetes mellitus and different glycemic control times on early osseointegration of dental implants by expression and significance of serum bone Gla protein (BGP) and alkaline phosphatase (ALP) levels in Zucker diabetic fatty (ZDF) rats after implantation. The animals were divided into three groups, each group with 11 rats and each rat with two dental implants (33 rats and 66 implants in total): group A, diabetic rats with dental implants (controls); group B, diabetic rats treated with insulin and implants placed simultaneously; and group C, diabetic rats treated with insulin until serum glucose at a constant level and then implants be placed. Levels of BGP and ALP in the serum were measured by enzyme-linked immunosorbent assay in each group. The software program SPSS (version 17.0 for Windows) was used to analyze all data; p < .05 was set as the level of statistical significance. At the 7th day, serum levels of BGP in group B and C were lower than that in group A (p > 0.05). At the 14th day, serum levels of BGP in group C were significantly higher (p < 0.05). After 30 days, compared with group A, the serum levels of BGP in group B and C seems to be lower. Compared with group A, the serum levels of ALP in group B and C were significantly higher, whereas the serum levels of ALP in group C seems to be higher than B (p < 0.05). The present results suggest that injection of delayed release microsphere of exenatide on ZDF rats can release exenatide at a steady rate and the blood glucose can be controlled at a constant level. Implant survival rates could be enhanced in DM subjects when blood plasma glucose level is under control; the serum levels of BGP in this study seems to have no relationship with local osseointegration, whereas the serum levels of ALP might offer insights into the activity of osseointegration around the implant surface.

Bushen Jianpi Huoxue Recipe in prevention and treatment of tibial stress injuries in rabbits

To explore the effects of Bushen Jianpi Huoxue Recipe, a compound traditional Chinese herbal medicine for tonifying the kidney, invigorating the spleen and promoting blood circulation, on tibial stress injuries in rabbits. Thirty-five mature male rabbits were used in the experiment, and randomly divided into 7 groups: sedentary control (SC) group, 1-week exercise (E-1W) group, 2-week exercise (E-2W) group, 3-week exercise (E-3W) group, 4-week exercise (E-4W) group, 3-week exercise and 1-week Chinese herbal medicine treatment (EMT-1W) group, and 4-week exercise and 2-week Chinese herbal medicine treatment (EMT-2W) group. There were 5 rabbits in each group. A rabbit model of tibial stress injuries was established by stimulating the rabbits to jump and run within a high-voltage and low-current electronic cage. Radiologic features, bone scintigraphy, histology and electron microscopy of rabbit tibia were observed, and the content of blood parathyroid hormone (PTH), bone gla protein (BGP) and testosterone was detected by using radioimmunoassay method. After 2-week exercise, changes in histology and osteocytes had a tendency towards stress injuries. Serum PTH and BGP levels were remarkably increased, while serum testosterone level was lower than that in the SC group. Three- and four-week continuous exercise resulted in tibial stress injuries, and the positive changes were observed in X-ray features and radionuclide images. Compared with E-3W group, the levels of serum BGP and testosterone were decreased remarkably. A series of positive results such as prevailing negativeness of X-ray features and radionuclide images, increasing process of osteogenesis, typical osteogenic phase of osteocytes and favorable transformation of biochemical markers was shown in EMT-1W and EMT-2W groups. It also showed remarkable rising levels of serum BGP and testosterone and remarkable reducing level of serum PTH in EMT-1W and EMT-2W groups as compared with E-1W and E-2W groups. Bushen Jianpi Huoxue Recipe can prevent and treat exercise-induced tibial stress injuries by stimulating new bone formation and increasing serum testosterone level.

RETRACTED: Effect of immobilization upon renal synthesis of 1,25-dihydroxyvitamin D in disabled elderly stroke patients

A 1,25-dihydroxyvitamin D [1,25-(OH)2D] deficiency and immobilization-related increased serum calcium concentration have been observed in hemiplegic stroke patients. To elucidate the influence of increased serum calcium concentration on bone metabolism, we measured serum biochemical indices and bone mineral density (BMD) in the second metacarpals of 170 elderly subjects with hemiplegic stroke and 72 age-matched healthy controls. Serum concentrations of 25-hydroxyvitamin D [25-(OH)D], 1,25-(OH)2D, ionized calcium, intact parathyroid hormone (PTH), intact bone Gla protein (BGP), and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) were measured. An increased serum calcium concentration (mean 2.543 mEq/L) was observed in this population and correlated negatively with the Barthel index (mean 66), indicating immobilization-induced bone resorption with consequent increased serum calcium. Decreased serum concentrations of 1,25-(OH)2D (mean 25.0 pg/mL) and serum 25-OHD concentration (mean 11.6 ng/mL) were noted. Serum PTH was not increased (mean 34.8 pmol/L). Serum levels of BGP were decreased significantly, whereas serum ICTP concentrations were elevated (mean 15.2 ng/mL). A strong negative correlation was seen between the serum calcium concentration and 1,25-(OH)2D (p < 0.0001). BMD of the second metacarpal in patients was decreased significantly compared with control subjects and highly correlated with 25-(OH)D and 1,25-(OH)2D concentrations. Immobilization-related increased serum calcium levels may inhibit PTH secretion, and thus 1,25-(OH)2D production. In addition, 25-(OH)D insufficiency also may contribute to decreased concentration of 1,25-(OH)2D.

Influence of Age and Sex in Serum Osteocalcin Levels in Thoroughbred Horses

In this study, we assessed the potential value of free serum osteocalcin or bone gla protein (BGP), the most abundant non collagenous matrix protein found in bone and dentin, to reflect changes of bone turnover in thoroughbred horses. Levels of osteocalcin were analyzed in serum samples of 54 clinically normal animals divided into three groups (A, B, C) according to age: 8, 16–18 and 24–36 months, in order to determine the standard for young horses of different age and sex. Serum BGP was measured by an in-house developed double antibody radioimmunoassay using bovine antigen. The mean BGP levels (ng/ml) were 45.65 ± 11.69; 33.65 ± 16.65; 15.08 ± 6.70 respectively for groups A, B and C; statistically significant differences were found between groups (A vs B and C; B vs C). Difference between males and females was found significant in group C with higher values in the females: 18.75 ± 5.00 against 14.43 ± 10.47 i n the males. This can be considered a sex related effect on BGP serum levels after the onset of puberty. Correlation coefficient between age and serum BGP for females and males were r = 0.598 (P < 0.001) and r = 00.807 (P < 0.001) respectively. A significant negative linear relationship could be established between these two parameters in males during the growth period. The regression equation between serum BGP and age for males was (month of age = 65.14–1.68·BGP). In the female group the gestation and lactation are variables that lower the correlation coefficient between age and serum BGP levels. These results suggest that serum BGP decreases in thoroughbred horses during the growth period, and significant differences between sexes were found only after the onset of puberty.

Evaluation of markers of bone and collagen turnover in patients with active and preclinical Cushing's syndrome and in patients with adrenal incidentaloma.

Although steroid-induced negative effects on bone and collagen have been well described in corticosteroid-treated patients, few studies have extensively evaluated bone and collagen turnover in patients with endogenous Cushing's syndrome. In this work serum bone-Gla protein (BGP), C-terminal cross-linked telopeptide of type I collagen (ICTP) and N-terminal propeptide of type III procollagen (PIIINP) levels were determined in patients with active (n = 12) and preclinical (n = 6) Cushing's syndrome, adrenal incidentalomas (n = 35) and in healthy controls (n = 28). In patients with overt Cushing's syndrome, serum BGP (0.9+/-0.2 ng/ml), ICTP (2.7+/-0.2 ng/ml) and PIIINP (1.9+/-0.2 ng/ml) levels were significantly lower (P < 0.0001) than in controls (5.5+/-0.2, 3.9+/-0.2 and 3.2+/-0.2 ng/ml respectively). In preclinical Cushing's syndrome, serum BGP (2.5+/-0.8 ng/ml), ICTP (2.2+/-0.1 ng/ml) and PIIINP (2.2+/-0.2 ng/ml) levels were significantly lower than in normal subjects (P < 0.0001, P < 0.0001 and P < 0.02 respectively), being similar to those recorded in overt Cushing's syndrome. In patients with adrenal incidentaloma, serum BGP (4.2+/-0.5 ng/ml) and ICTP (2.9+/-0.2 ng/ml) levels were significantly lower than those found in controls (P < 0.05 and P < 0.001 respectively), while serum PIIINP levels (3.6+/-0.2 ng/ml) did not differ from those of normals. In particular, 9/35 patients with adrenal incidentaloma had markedly depressed BGP levels (<2.0 ng/ml; mean 0.8+/-0.1 ng/ml): all patients of this subgroup showed an exaggerated 17-hydroxyprogesterone increase after ACTH administration. In the same patients, serum ICTP (3.0+/-0.4 ng/ml) and PIIINP (3.6+/-0.2 ng/ml) levels did not differ from those found in the incidentaloma group. In conclusion, our study indicates that bone and collagen turnover are markedly affected in patients with overt and preclinical Cushing's syndrome. Although patients with adrenal incidentaloma do not show any signs or symptoms of overt hypercortisolism, the presence of reduced BGP and ICTP levels might be considered a further index of an 'abnormal' pattern of steroid secretion in some of them. As a consequence, the presence of early alterations in markers of bone turnover might be useful for selecting those patients who need more accurate follow-up of the adrenal mass.

Serum osteocalcin and bone mineral density at various skeletal sites: A study performed with three different assays

The purposes of this study were threefold: (1) to compare values obtained by three conventional radioimmunoassays for serum bone-gla-protein (BGP) in a population of normal women, (2) to study the relationship between serum BGP and bone mineral density (BMD) measured at four different skeletal sites (lumbar spine, proximal femur, proximal and ultradistal radius), and (3) to compare the results obtained by the three assays with conventional markers of bone turnover. Ninety-seven normal women (age range 25 to 75 years, mean ± SD = 54.3 ± 10.9 years) were studied. Three independent assays were used to measure serum osteocalcin levels: a heterologous radioimmunoassay (RIA) (A) (Incstar Co., Stillwater, Minn.), a homologous RIA (B) (Nichols Institute, San Juan Capistrano, Calif.), and a two-site immunoradiometric assay (C) (Cis Biointernational, Gif-sur-Yvette, France). Mean ± SD values of serum osteocalcin in the group as a whole were 4.05 ± 1.37 μg/L by assay A, 6.03 ± 2.90 μg/L by assay B, and 22.67 ± 7.52 μg/L by assay C. Serum osteocalcin levels increased linearly with age; however, no correlation between serum BGP (whatever the assay used) and age was observed when only postmenopausal women were taken into account. When the effect of age was held constant by means of partial correlation analysis, only serum BGP levels measured by assays B and C were still inversely related with lumbar spine and ultradistal radius BMD; the latter assay was also weakly correlated with Ward's triangle BMD. After all the biochemical and clinical variables taken into consideration were introduced in a multiple regression equation, serum BGP still represented an important predictor of ultradistal radius and lumbar spine BMD only. Regarding relationships with other markers of bone turnover, the assay C in general showed the highest r values. In conclusion, our results indicate that commercially available BGP assays differ analytically and clinically; furthermore for the first time they show the existence of an inverse correlation between serum osteocalcin levels (which reflects bone turnover at the time of examination) and bone mass (which at a given time represents the balance of all previous metabolic events), after the influence of aging is excluded.

Treatment of isolated hypogonadotropic hypogonadism effect on bone mineral density and bone turnover.

Isolated hypogonadotropic hypogonadism (IHH) presents with delayed puberty in the late teens or early twenties, with a period of testosterone deficiency during active growth. The aims of the study were to determine 1) whether long term treatment of IHH results in normalization of bone density (BMD) and bone turnover, and 2) whether BMD and bone turnover respond to increasing doses of hCG. We studied 10 men, aged 26-46 yr, with IHH who were treated with hCG or testosterone esters (Sustanon) for 2-22 yr, with age at the start of treatment between 17-29 yr, and 10 age- and body weight-matched normal men as a control group. At baseline, lumbar spine, femoral neck, trochanter, and Ward's triangle BMD values were decreased, and serum bone Gla-protein, bone alkaline phosphatase, and urinary pyridinoline, deoxypyridinoline, and N-terminal telopeptide of type I collagen were increased compared with control values (by paired t test, P = 0.02, 0.03, 0.01, 0.05, 0.002, 0.02, 0.02, 0.007, and 0.006, respectively). The age at initial therapy was significantly correlated with total body BMD (r = -0.73; P = 0.017) and lumbar spine BMD (r = -0.756; P = 0.0097). Serum free testosterone was correlated with total body and trochanter BMD (r = 0.635; P = 0.048 and r = 0.629; P = 0.05), and serum free estradiol was correlated with total body and trochanter BMD (r = 0.641; P = 0.045 and r = 0.634; P = 0.048). Six of the 10 patients were recruited for a longitudinal study in which the dose of hCG was increased monthly from 2000 i.u. twice per week to 6000 i.u. twice per week. After increasing doses of hCG, levels of serum testosterone and estradiol and total body BMD increased significantly (by paired t test P = 0.001, 0.003, and 0.01, respectively). Serum bone Gla-protein levels increased by the first month and then decreased (paired t test, corrected by Bonferroni's method). Serum bone alkaline phosphatase and urinary N-terminal telopeptide of type I collagen/creatinine levels decreased significantly after increasing the dose of hCG. We conclude that patients with IHH who have serum testosterone within the laboratory reference range may require a higher dose of hCG to normalize BMD and bone turnover.

Serum bone Gla-protein increases following short-term oral administration of active vitamin D3 in the elderly with vitamin D deficiency

Serum bone Gla-protein (BGP) is produced by osteoblasts in a vitamin K-dependent process. It is well known that serum BGP levels increase after oral administration of active vitamin D3 in postmenopausal women and patients with chronic renal failure before dialysis. These findings indicate that active vitamin D3 increases the BGP production by osteoblasts. In the present study, a daily oral dose of 2 micrograms of 1 alpha (OH)D3 was administered to 10 elderly males (age, 75.0 +/- 10.9 years) and 8 young males (age, 29.0 +/- 3.2 years) to compare the changes in serum BGP levels between the two groups. None of the subjects had severe renal or hepatic dysfunction or abnormalities in calcium (Ca) metabolism. Serum BGP and 1,25(OH)2D levels in both groups were measured before the initial administration, at 24 h and at 1, 2 and 3 weeks after the start of administration. Serum parathyroid hormone (m-PTH), alkaline phosphatase (ALP), Ca and phosphorus levels were also measured in the elderly group. Serum BGP levels before the initial administration were 4.63 +/- 1.8 ng/ml in the elderly group and 4.33 +/- 0.92 ng/ml in the young group, with no significant difference between the two groups. In both group serum 1,25(OH)2D levels were slightly increased at 24 h after administration. In the elderly group serum BGP levels increased significantly to 11.5 +/- 3.0 ng/ml, an increase of approximately 250%, 1 week after the initial administration and the increase was maintained for up to 3 weeks after the administration commenced. However, no changes in serum BGP levels were noted in the young group. In the elderly group serum m-PTH levels were 544 +/- 257 pg/ml, almost the upper normal limit, before, and decreased slightly after, the administration of 1 alpha (OH)D3. Serum ALP levels also decreased slightly after the administration and serum Ca levels were slightly increased, however, the changes were within normal limits. We conclude that osteoblastic function is activated after short-term administration of active vitamin D3 in vitamin D deficient elderly subjects.

Serum bone Gla protein and carboxyterminal cross-linked telopeptide of type I collagen in patients with Cushing's syndrome.

Serum bone Gla protein, a marker of bone formation, and carboxyterminal cross-linked telopeptide of type I collagen levels, an index of bone resorption, were evaluated in eight patients with active Cushing's syndrome and in four with 'preclinical' Cushing's syndrome, before and after surgery. In basal conditions, serum bone Gla protein levels were significantly lower (p < 0.0001) in patients with active Cushing's syndrome (1.0 +/- 0.35 ng/ml) than in controls (5.4 +/- 0.15 ng/ml); two out of four patients with the 'preclinical' form had reduced bone Gla protein levels, while in the other two cases levels were in the normal range. Serum levels of carboxyterminal cross-linked telopeptide of type I collagen (3.0 +/- 0.4 ng/ml), although slightly reduced, were similar to those recorded in controls (4.1 +/- 0.3 ng ml), both in patients with active and with preclinical Cushing's syndrome. After surgery serum levels of both marker proteins significantly increased in seven out of eight patients with active Cushing's syndrome; in one patient, who was not cured after surgery, bone Gla proteins levels remained lower than in normals, while levels of carboxyterminal cross-linked telopeptide of type I collagen had a transient increase after six months. In the two patients with a 'preclinical' Cushing's syndrome who underwent surgery, a significant rise of the levels of both marker proteins was observed, similar to that observed in patients with active Cushing's syndrome. It was concluded that serial determinations of these new markers of bone formation and resorption may be usefully employed to follow-up the clinical course of Cushing's syndrome and provide information on the rate of bone turnover in response to medical and/or surgical therapies. Moreover, the evaluation of these markers in preclinical states of Cushing's syndrome might suggest the need for surgery.

Modifications of biochemical markers of bone and collagen turnover during corticosteroid therapy.

Serum bone Gla protein (BGP), carboxyterminal cross-linked telopeptide of type I collagen (ICTP) and aminoterminal propeptide of type III procollagen (PIIINP) levels were determined in 8 patients with autoimmune disorders (2 with systemic lupus erythematosus, 3 with rheumatoid arthritis, 2 with Sjögren's syndrome and 1 with mixed connective tissue disease) before and after 1, 2 and 4 months of treatment with oral prednisone (at a dosage of 1 mg/kg bw/day, p.o. during the first month, then reduced to 0.1-0.2 mg/kg bw/day). Before treatment mean serum BGP (mean +/- SE: 5.3 +/- 0.4 ng/ml) and ICTP (2.8 +/- 0.2 ng/ml) levels were similar to those recorded in an age and sex matched control group (n = 40: 5.4 +/- 0.1 ng/ml and 4.1 +/- 0.3 ng/ml, respectively). On the other hand, serum PIIINP levels (2.2 +/- 0.3 ng/ml) were significantly (p < 0.008) lower than those found in controls (3.3 +/- 0.2 ng/ml). During glucocorticoid therapy, serum BGP levels significantly decreased after 1 month (2.9 +/- 0.4 ng/ml; P < 0.001), but returned to baseline values after 2 and 4 months of treatment (4.7 +/- 0.4 ng/ml and 5.3 +/- 0.3 ng/ml, respectively). On the contrary, no significant changes were observed in serum ICTP levels during treatment (1st month: 2.7 +/- 0.4 ng/ml; 2nd month: 3.0 +/- 0.4 ng/ml; 4th month: 2.4 +/- 0.3 ng/ml). Serum PIIINP mean concentration significantly decreased after 1 (1.6 +/- 0.3 ng/ml; P < 0.004) and 2 months of glucocorticoid administration (1.5 +/- 0.2 ng/ml; P < 0.01); after 4 months, serum PIIINP levels were again reduced as before therapy (1.8 +/- 0.2 ng/ml). In conclusion, our study shows the presence of normal bone turnover indexes and of altered collagen synthesis in patients with autoimmune disorders. The use of high doses of oral steroids is associated with a prompt decrease of bone formation and collagen synthesis, without any significant changes in bone resorption; however, the negative effects on bone formation and collagen synthesis seem to revert after lowering corticosteroid dosage. Serial determinations of the markers of bone and collagen turnover are able to give useful and reliable information on the peripheral effects of steroids excess.

Utilization of cyclosporine H to elucidate the possible mechanisms of cyclosporine A-induced osteopenia in the rat

The immunosuppressive agent cyclosporine A (CsA) produces in vivo in the rat marked osteopenia and elevation of serum bone gla protein (BGP) that reflects the high bone turnover and increased circulating levels of 1,25-dihydroxyvitamin D [1,25(OH) 2D]. Cyclosporine H (CsH), a d- N-MeVal 11 analog of CsA, is not immunosuppressive, and in contrast to CsA, it neither binds to cyclophilin nor alters cytokine activity. This distinction between CsH and CsA provides a means of elucidating whether CsA exerts an effect on bone and 1,25(OH) 2D via immune-mediated mechanisms. We therefore studied three groups of male Sprague-Dawley rats (300 to 350 g body weight [BW]) randomly divided to receive either cyclosporine vehicle, CsA, or CsH 15 mg/kg BW by daily gavage for 28 days. Blood samples were assayed for ionized calcium (Ca 2+), serum BGP, serum parathyroid hormone (PTH), and 1,25(OH) 2D by specific radioimmunoassay on days 0, 14, and 28. Histomorphometric evaluations were performed on the right tibia after tetracycline and calcein labeling and killing of the rats at the end of 28 days of treatment. In CsA-treated rats, serum BGP levels were significantly increased (155.2 ± 30.7 ng/mL v 107.3 ± 16.8 and 111.5 ± 13.1 at day 28, P < .05) compared with control and CsH groups, respectively. Similarly, 1,25(OH) 2D was significantly increased in CsA-treated rats versus control and CsH groups (134.9 ± 35.3 pg/mL v 70.2 ± 16.6 and 69.8 ± 20.6 [ P < .05], respectively). PTH and CA 2+ were unchanged. Histomorphometrically, the CsA-treated group showed a significant loss in bone volume ([BV] P < .05) and an increase in the indices of bone remodeling compared with the control group. The CsH group showed no significant alteration in indices of bone remodeling compared with the control group. These results indicate that the accelerated bone remodeling with osteopenia and the increased production of 1,25(OH) 2D is probably mediated by immune mechanisms.

Influence of age on cyclosporin A-induced alterations in bone mineral metabolism in the rat in vivo

Cyclosporin A (CsA) administered to actively growing young rats produces a high-turnover osteopenia. We investigated and compared the effect of CsA on the bone mineral metabolism in young rats with that of older rats, which have a lower rate of bone turnover. A group of 24 young (9 weeks) and 24 older (9 months) male Sprague-Dawley rats were orally administered 15 mg/kg of CsA or placebo daily for 24 days. Rats were weighed and serum assayed serially for bone gla protein (BGP), parathyroid hormone, ionized calcium, blood urea nitrogen, creatinine, and 1,25-dihydroxyvitamin D [1,25-(OH)2D]. After sacrifice, histomorphometric analysis was performed on undecalcified proximal tibial metaphysis with double-fluorescent labeling. Serum BGP levels were significantly elevated in both young and older rats administered CsA, and 1,25-(OH)2D levels were significantly elevated in CsA-treated young rats more than in older rats. Body weight was significantly reduced in CsA-treated older rats. There were mild but significant alterations in renal function in both groups receiving CsA. In the most comprehensive examination to date of the effects of CsA on bone histomorphometry, both young (-44%) and older rats (-20%) lost significant amounts of trabecular bone compared to their respective controls. Bone loss in young rats was mainly due to a reduced number of trabecular; older rats lost mainly trabecular thickness. Microanatomic nodal studies were consistent with these results. These data demonstrate that although cancellous bone loss induced by CsA is more marked in young rats, older rats with slower bone turnover are also at risk.

Effect of interferon α on calcium and bone metabolism in patients with chronic hepatitis

We investigated the changes of natural type of interferon-α (IFNα) on calcium and bone metabolism in patients with chronic hepatitis C. Natural IFNα was injected intramuscularly at daily doses of 6 million units for 2 weeks to 10 patients with chronic hepatitis caused by hepatitis C virus, and followed by 3-times-a-week administration for another 10 weeks. The markers for bone metabolism including serum bone-Gla protein (BGP) concentration and urinary excretion of pyridinolines (pyridinoline and deoxypyridinoline) were measured before and during the treatment. The twelve-week administration of IFNα reduced pyridinoline excretion from 39.7±13.3 (SD) pmol/µ mol · creatinine to 28.3±8.1 pmol/µ mol · creatinine (p<0.06), and that of deoxypyridinoline from 6.51±3.38 pmol/µ mol · creatinine to 3.91±2.07 pmol/µ mol · creatinine (p<0.01), although serum levels of BGP and parathyroid hormone (PTH) did not show any significant changes. The ratio of BGP/urinary pyridinoline increased from 0.098±0.074 to 0.198±0.093 at the end of 12th week (p<0.03), and that of BGP/deoxypyridinoline increased from 0.630±0.502 to 1.550±0.788 at 12th week (p<0.02). Serum aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) did not change significantly during the study. IFNα reduces bone resorption in contrast with insignificant effects on bone formation in patients with mild to moderate hepatitis. The effects on calcium and bone metabolism may give beneficial effects for patients with high turnover osteoporosis.

Growth hormone treatment in adults with GH deficiency: Effects on new biochemical markers of bone and collagen turnover

Serum bone Gla protein (BGP) and bone alkaline phosphatase (B-AP), markers of bone formation, carboxyterminal cross-linked telopeptide of type I collagen (ICTP), marker of bone resorption, and aminoterminal propeptide of type III procollagen (PIIINP) levels, index of collagen synthesis, were determined in 8 adults (mean age +/- SE: 29.6 +/- 1.2 yr) with childhood onset GHD before and after 3 and 6 months of recombinant GH treatment (0.5 IU/kg/week). Before treatment, mean BGP (3.8 +/- .5 ng/ml) and B-AP (44.9 +/- 6.9 IU/L) were significantly (P < 0.001 and p < 0.05, respectively) lower than those recorded in normals (5.4 +/- 0.1 ng/ml and 61.8 +/- 1.9 IU/L, respectively), while serum ICTP and PIIINP levels were similar to those found in controls (ICTP: 4.7 +/- 0.8 vs 4.1 +/- 0.3 ng/ml; PIIINP: 3.7 +/- 0.6 vs 3.2 +/- 0.2 ng/ml). BGP and ICTP levels significantly (p < 0.005) increased after 3 (28.4 +/- 5.3 ng/ml and 17.5 +/- 2.8 ng/ml, respectively) and 6 months (25.1 +/- 5.0 ng/ml and 15.0 +/- 1.9 ng/ml, respectively) of recombinant GH treatment. B-AP levels significantly (p < 0.01) increased during the treatment (basal: 44.9 +/- 6.9 IU/L, 3rd month: 173.6 +/- 40 IU/L, 6th month: 194.4 +/- 40 IU/L), while non B-AP levels remained similar to those recorded in basal condition. Serum PIIINP levels significantly (p < 0.0001) rose up after 3 (12.5 +/- 1.4 ng/ml) and 6 months (10.2 +/- 0.8 ng/ml). Serum BGP and ICTP levels were directly (r = 0.85, p < 0.001; r = 0.53, p < 0.01) correlated with serum IGF-I levels.(ABSTRACT TRUNCATED AT 250 WORDS)

New markers of bone and collagen turnover in children and adults with growth hormone deficiency.

Serum bone Gla protein (BGP), a marker of osteoblastic function, serum carboxyterminal cross-linked telopeptide of type I collagen (ICTP), a marker of bone resorption, and serum aminoterminal propeptide of type III procollagen (PIIINP) levels, an index of collagen synthesis, were determined in seven children and eight adults with congenital growth hormone deficiency (GHD). In children with GHD, serum BGP (mean +/- s.e.: 12.9 +/- 0.7 ng/ml), ICTP (8.3 +/- 1.3 ng/ml) and PIINP (3.5 +/- 0.5 ng/ml) levels were significantly lower (P < 0.001) than those recorded in normal children (BGP 18.9 +/- 0.8 ng/ml, ICTP 14.4 +/- 0.5 ng/ml and PIIINP 6.7 +/- 0.7 ng/ml). Total alkaline phosphatase (184.7 +/- 13.4 IU/l) and bone alkaline phosphatase (77.8 +/- 4.1 IU/l) levels were also significantly lower (P < 0.0001) than in controls (338.1 +/- 14.9 IU/l and 181.0 +/- 7.8 IU/l, respectively). Serum BGP, ICTP and PIIINP levels were not significantly correlated with height velocity values. In adults with GHD, mean BGP levels (3.8 +/- 0.3 ng/ml) were significantly lower (P < 0.0001) than those recorded in normals (5.4 +/- 0.1 ng/ml). On the contrary, serum ICTP levels were similar to those found in controls (patients: 4.7 +/- 0.8 ng/ml vs normals: 4.1 +/- 0.3 ng/ml), suggesting the presence of a normal resorption activity associated with a reduced osteoblastic function. This finding was also confirmed by the presence of reduced bone alkaline phosphatase levels (GHD: 44.9 +/- 6.9 IU/I vs controls: 58.3 +/- 2.0 IU/I; P<0.02), while the less specific total alkaline phosphatase levels (119.5 +/- 14.8 IU/I) were similar to those recorded in normal subjects (122.3 +/- 4.0 IU/I). Serum PIIINP levels (3.7 +/- 0.6 ng/ml) were similar to those recorded in normals (3.2 +/- 0.2 ng/ml), suggesting that in adulthood the collagen turnover is not negatively influenced by the chronic GHD. No significant correlations were found between BGP/ICTP/PIIINP and IGF-I levels. In conclusion, our data show that in children with GHD the lack of GH insulin-like growth factor-I (IGF-I) effects on bone and collagen turnover is associated with a significant reduction of bone turnover (low bone formation plus low bone resoRption) and collagen synthesis. On the contrary, adult GHD seems to exert less relevant effects on bone and collagen turnover, probably due to the fact that in adult life further hormones or local factors might partially counteract the negative consequences of chronic GH-IGF-I deficiency.

MINERAL METABOLISM, OSTEOBLASTIC FUNCTION AND BONE MASS IN CHRONIC ALCOHOLISM

The role of ethanol as a risk factor for osteopenia was studied in alcoholic subjects without liver cirrhosis. The study was carried out in 58 male subjects classified into three groups: (1) 26 heavy drinkers, alcohol intake more than 100 g ethanol/day for more than 10 years; (2) 13 moderate drinkers, 60-100 g ethanol/day; (3) 19 healthy non-drinkers who served as control subjects. None of the drinkers had liver cirrhosis (normal clinical and biochemical data and/or liver biopsy). Mineral metabolism and serum bone Gla-protein (BGP) were studied while they were active drinkers and after they had abstained from ethanol for 7 days. Bone mineral density (BMD) was determined at the beginning of the study. Osteopenia was observed in 23% of the heavy drinkers. We found a significant inverse correlation between BMD and an index of cumulative alcohol intake. Heavy and moderate drinkers had significantly lower mean BGP values (1.6 +/- 0.4 and 1.9 +/- 0.3 ng/ml) (P < 0.01 for both) than controls (3.5 +/- 0.4 ng/ml); these values increased significantly (2.9 +/- 0.4 ng/ml; P < 0.01) after 7 days of abstinence. The data show that chronic ethanol ingestion can induce osteopenia regardless of the absence of liver cirrhosis, and that some relationship can be expected between the amount and duration of ethanol consumption and the degree of bone loss. The low serum BGP levels in drinkers are reversible upon withdrawal of ethanol, suggesting that reduction of osteoblastic activity is probably the main factor responsible for alcohol-associated bone disease.

The diagnostic and prognostic value of serum bone Gla protein (osteocalcin) in patients with recurrent breast cancer.

Serum bone Gla protein (S-BGP), a marker of bone metabolism, was measured in 60 patients included in a staging programme for recurrent breast cancer. Other diagnostic procedures comprised S-alkaline phosphatase (S-AP), bone scan (B-scan), bilateral iliac crest bone marrow biopsies, and radiological bone survey. The sites of recurrence were bone (61%), bone marrow (46%), soft tissue (52%), lung (13%), pleura (11%), liver (4%), and brain (2%). Radiology and bone biopsy served as key diagnoses as to the presence or absence of bone metastases. The diagnostic efficiency of B-scan and S-AP was greater than that of S-BGP, and the result of BGP measurement was associated with neither extent nor number of bone metastases. However, the BGP values were significantly lower in patients who had visceral metastases, and the median duration of survival after recurrence was 13 months for patients with low S-BGP levels (= < 2.0 nmol l-1), compared to 18 months for patients with medium S-BGP values (2.0-2.9 nmol l-1), and 25 months for patients with high values (> 3.0 nmol l-1) (p = 0.19). Analyses of the simultaneous effect of univariate prognostic factors were performed using the Cox proportional hazards model. S-alkaline phosphatase (S-AP) and S-BGP were the only significant, independent prognostic factors.

REDUCED SPINAL AND FEMORAL BONE MASS AND DERANGED BONE MINERAL METABOLISM IN CHRONIC ALCOHOLICS

Prevalence and factors which may influence the development of osteoporosis have been assessed in 32 chronic alcoholic males by measuring the bone mineral density (BMD) of the lumbar spine and femoral neck by dual photon absorptiometry. Serum bone Gla-protein, as an index of bone formation, 25-hydroxyvitamin D, testosterone and cortisol levels were also measured. Eleven patients (34%) had osteoporosis. In seven the lumbar BMD was below the fracture threshold. Lumbar and femoral neck age-matched BMD were below mean normal values in 20 and in 23 patients, respectively. Moreover, the age-matched BMD was significantly lower in the femoral neck (91.7 +/- 14.4%) than in the lumbar spine (100.1 +/- 17.1%) (P < 0.001). Duration of alcoholism was significantly higher in patients with age-matched BMD below 100% than in those with age-matched BMD above 100%. Bone GLA-protein and 25- hydroxyvitamin D were below normal levels in 67% and 56% of patients, respectively. Serum testosterone was normal in all but two patients, and cortisol was within normal values in all patients tested. In addition a direct correlation was found between the days of abstinence before the study and serum levels of bone GLA-protein (r = 0.64, P < 0.001). In conclusion, chronic alcoholics frequently have bone loss of the lumbar spine and femoral neck related with the duration of alcohol intake. The correlation between bone-GLA protein levels and the days of abstinence suggests that alcohol directly depresses bone formation. Likewise, the low levels of vitamin D also support that this deficiency may contribute to the development of osteopenia in chronic alcoholism.