Boron intake, osteocalcin polymorphism and serum level in postmenopausal osteoporosis

The relationship between daily boron intake and osteocalcin-mediated osteoporosis was studied in boron-exposed postmenopausal women. It is known that boron and osteocalcin are important in bone metabolism, however the effect of boron in bone metabolism has not been fully discovered. The study was performed on 53 postmenopausal women aged 55-60 living in parts of Balikesir, Turkey, where the subjects are naturally exposed to high (≥1 mg/L) or low (<1 mg/L) boron concentration in drinking water. 24-h urine samples were collected from all participants and creatinine clearance was detected. Boron intake levels of the subjects whose clearance levels were between 80-124 mL/min were measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) in urine samples. Serum osteocalcin levels of the subjects were measured by osteocalcin enzyme-linked immunosorbent assay (ELISA) kit. Osteocalcin polymorphism rs1800247 was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Serum osteocalcin levels in boron-exposed postmenopausal women were significantly higher than that of control group (P ≤ 0.05) and the correlation between the serum osteocalcin level and rs1800247 polymorphism was not significant in both groups (P > 0.05). The differences in the distribution of osteocalcin genotypes and alleles in postmenopausal women were not significant between the boron exposed and the control groups (P > 0.05). Serum osteocalcin level in the CC genotype was significantly higher compared to the TC genotype in boron-exposed group (P ≤ 0.05). Our study suggests that daily boron intake of 1 mg/L may affect bone metabolism in postmenopausal women positively.

Comprehensive metabolic characterization of serum osteocalcin action in a large non-diabetic sample

Recent research suggested a metabolic implication of osteocalcin (OCN) in e.g. insulin sensitivity or steroid production. We used an untargeted metabolomics approach by analyzing plasma and urine samples of 931 participants using mass spectrometry to reveal further metabolic actions of OCN. Several detected relations between OCN and metabolites were strongly linked to renal function, however, a number of associations remained significant after adjustment for renal function. Intermediates of proline catabolism were associated with OCN reflecting the implication in bone metabolism. The association to kynurenine points towards a pro-inflammatory state with increasing OCN. Inverse relations with intermediates of branch-chained amino acid metabolism suggest a link to energy metabolism. Finally, urinary surrogate markers of smoking highlight its adverse effect on OCN metabolism. In conclusion, the present study provides a read-out of metabolic actions of OCN. However, most of the associations were weak arguing for a limited role of OCN in whole-body metabolism.

Periodontal disease exacerbates systemic ovariectomy-induced bone loss in mice

Periodontal pathogens and/or inflammatory products from periodontitis participate in the development or progression of systemic diseases. In this context, periodontitis acts as a modifying factor to systemic health, including diabetes and cardiovascular diseases. Osteoporosis is an increasingly prevalent condition in our aging population and considered a risk factor for periodontal disease, but the effect of periodontitis on systemic bone homeostasis is unknown. We thus evaluated the effects of experimental periodontitis (EP) on systemic bone loss and the influence of estrogen deficiency in this context, using a mouse model of combined periodontitis and osteoporosis. Experimental periodontitis (EP) was induced by a ligature insertion around the mandibular first molars and Porphyromonas gingivalis infection. Three-dimensional microcomputed tomographic analyses performed 48days following infection revealed that EP and ovariectomy (OVX) induced a significantly higher femoral and mandibular bone loss compared to EP or OVX alone. EP alone did not induce systemic bone loss. In addition, the EP+OVX and EP groups showed significantly higher levels of tumor necrosis factor (TNF)-α than OVX and control groups at end point. These results suggest that periodontitis could be a risk factor for systemic bone loss, especially in post-menopausal women, and warrant further clinical investigations to confirm this association and propose adapted prophylactic and curative therapies.

Bone turnover markers in medicamentous and physiological hyperprolactinemia in female rats

BACKGROUND/AIM

There is a lack of data on the effects of prolactin on calcium metabolism and bone turnover in hyperprolactinemia of various origins. The aim of this study was to compare the influence of medicamentous and physiological hyperprolactinemia on bone turnover in female rats.

METHODS

Experimental animals (18 weeks old, Wistar female rats) were divided as follows: the group P - 9 rats, 3 weeks pregnant; the group M3-10 rats that were intramuscularly administrated sulpirid (10 mg/kg) twice daily for 3 weeks, the group M6 - 10 rats that were intramuscularly administrated with sulpirid (10 mg/kg) twice daily for 6 weeks, and age matched nulliparous rats as the control group: 10 rats, 18-week-old (C1) and 7 rats, 24 weeks old (C2). Laboratory investigations included serum ionized calcium and phosphorus, urinary calcium and phosphorous excretion, osteocalcin and serum procollagen type 1 N-terminal propeptide (P1NP).

RESULTS

Experimental animals in the group P compared to the control group, displayed lower mean serum ionized calcium (0.5 +/- 0.2 vs 1.12 +/- 0.04 mmol/L; p < 0.001); higher mean serum phosphorus (2.42 +/- 0.46 vs 2.05 +/- 0.2 mmol/L; p < 0.05); increased urinary calcium (3.90 +/- 0.46 vs 3.05 +/- 0.58; p < 0.01) and significantly increased P1NP (489.22 +/- 46.77 vs 361.9 +/- 53.01 pg/mL; p < 0.001). Experimental animals in the group M3 had significantly decreased P1NP, compared to the contol group. Prolongated medicamentous hyperprolactinemia (the group M6) induced increased serum ionized calcium (1.21 +/- 0.03 vs 1.15 +/- 0.02 mmol/L; p < 0.001); decreased serum phosphorus (1.70 +/- 0.13 vs 1.89 +/- 0.32 mmol/L; p < 0.001); decreased osteocalcin and P1NP.

CONCLUSIONS

Physiological hyperprolactinemia does not have such harmful effect on bone metabolism as medicamentous hyperprolactinemia. Chronic medicamentous hyperprolactinemia produces lower serum levels of bone formation markers. Assessment of bone turnover markers in prolongated medicamentous hyperprolactinemia provides an opportunity for earlier diagnosis of bone metabolism disturbances and should be considered as mandatory.

Tactile/kinesthetic stimulation (TKS) increases tibial speed of sound and urinary osteocalcin (U-MidOC and unOC) in premature infants (29-32weeks PMA)

Preterm delivery (<37 weeks post-menstrual age) is associated with suboptimal bone mass. We hypothesized that tactile/kinesthetic stimulation (TKS), a form of infant massage that incorporates kinesthetic movement, would increase bone strength and markers of bone accretion in preterm infants. Preterm, AGA infants (29-32 weeks) were randomly assigned to TKS (N=20) or Control (N=20). Twice daily TKS was provided 6 days per week for 2 weeks. Control infants received the same care without TKS treatment. Treatment was masked to parents, health care providers, and study personnel. Baseline and week two measures were collected for tibial speed of sound (tSOS, m/sec), a surrogate for bone strength, by quantitative ultrasound (Sunlight8000) and urine markers of bone metabolism, pyridinium crosslinks and osteocalcin (U-MidOC and unOC). Infant characteristics at birth and study entry as well as energy/nutrient intake were similar between TKS and Control. TKS intervention attenuated the decrease in tSOS observed in Control infants (p<0.05). Urinary pyridinium crosslinks decreased over time in both TKS and CTL (p<0.005). TKS infants experienced greater increases in urinary osteocalcin (U-MidOC, p<0.001 and unOC, p<0.05). We conclude that TKS improves bone strength in premature infants by attenuating the decrease that normally follows preterm birth. Further, biomarkers of bone metabolism suggest a modification in bone turnover in TKS infants in favor of bone accretion. Taken together, we speculate that TKS improves bone mineralization.

[State of bone structures in children with acute leukemia, experiencing unfavorable factors from Chernobyl accident]

The authors present an assessment of bone structure condition in children with acute leukemia. The changes in the collagen molecule, amino acid composition of urine and proteins reparation processes were revealed. Calcium phosphate excretion in the patients urine were increased. The serum osteocalcin level and colony formation efficiency of bone marrow fibroblasts in acute leukemia patients are lower than in control group. In the initial period of the disease 32% of patients have disturbancies in their endocrine status. The bone structure violation is combined with unfavorable disease outcome. The effectiveness of the treatment and prevention steps in acute leukemia patients depends on the leukemic process stage.

Sustained activation of renal N-methyl-D-aspartate receptors decreases vitamin D synthesis: a possible role for glutamate on the onset of secondary HPT

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are tetrameric amino acid receptors that act as membrane calcium channels. The presence of the receptor has been detected in the principal organs responsible for calcium homeostasis (kidney, bone, and parathyroid gland), pointing to a possible role in mineral metabolism. The aim of this study was to test the effect of NMDAR activation in the kidney and on 1,25(OH)₂D₃ synthesis. We determined the presence of NMDAR subunits in HK-2 (human kidney cells) cells and proved its functionality. NMDA treatment for 4 days induced a decrease in 1α-hydroxylase levels and 1,25(OH)₂D₃ synthesis through the activation of the MAPK/ERK pathway in HK-2 cells. In vivo administration of NMDA for 4 days also caused a decrease in blood 1,25(OH)₂D₃ levels in healthy animals and an increase in blood PTH levels. This increase in PTH induced a decrease in the urinary excretion of calcium and an increase in urinary excretion of phosphorous and sodium as well as in diuresis. Bone turnover markers also increased. Animals with 5/6 nephrectomy showed low levels of renal 1α-hydroxylase as well as high levels of renal glutamate compared with healthy animals. In conclusion, NMDAR activation in the kidney causes a decrease in 1,25(OH)₂D₃ synthesis, which induces an increase on PTH synthesis and release. In animals with chronic kidney disease, high renal levels of glutamate could be involved in the downregulation of 1α-hydroxylase expression.

[Progress in the treatment of osteoporosis]

The purpose of the treatment of osteoporosis is to reduce fracture risk and maintain/improve quality of life (QOL). The criteria for initiating pharmacotherapy to prevent fragility fractures should be provided separately from the criteria for diagnosis of osteoporosis. In Japan, low bone mineral density (BMD), prevalent fracture, and age are established as fracture risk factors from available data. A meta-analysis conducted by the WHO assured that excessive drinking (2 units a day or more), current smoking, and a family history of hip fracture are fracture risk factors. Moreover, in WHO technical report 921, high levels of CTX, a bone resorption marker as well as uncarboxylated osteocalcin were cited as risk factors of hip fracture, which can be measured in medical practice in Japan. Pharmacotherapy should be initiated with the consideration of the above risk factors. Recent large scale of randomized control trial(RCT), followed by meta-analysis demonstrated that bisphosphonates such as alendronate and risedronate as well as raloxifene (selective estrogen receptor modulator) are top grade of drugs which prevent fragility fracture in osteoporotic patients. Now, it is possible to perform evidence-based medicine in daily medical practice. As for secondary osteoporosis, along with treatment of underlying diseases, treatment aimed at preventing bone loss is necessary in many cases. Accumulating evidence is available about increased fracture threshold in glucocorticoid- and diabetes mellitus-induced osteoporosis. Therefore, early treatment should be appropriate in these cases. In osteoporotic patients, atherosclerotic vascular calcification as well as abnormal lipid metabolism often coexists. Multiple vertebral fractures followed by kyphosis often causes functional disorders of the digestive and respiratory systems.

Role of subchondral bone in osteoarthritis development: a comparative study of two strains of guinea pigs with and without spontaneously occurring osteoarthritis

OBJECTIVE

To evaluate the relationships among cartilage and subchondral bone before and after the onset of cartilage degeneration in the Hartley guinea pig model of spontaneous osteoarthritis (OA) as compared with those in Weiser-Maple guinea pigs, which do not develop OA.

METHODS

Mice from each strain were used at ages 2, 3, 5, and 8 months (n = 7 at each time point). The region observed was the medial tibial plateau. Cartilage degeneration was evaluated histologically. Subchondral bone structure was evaluated based on subchondral bone plate thickness and subchondral cancellous bone trabecular parameters calculated from the microfocal computed tomography 3-dimensional reconstruction image. The bone mineral density (BMD) of the subchondral cancellous bone as well as levels of urinary N-telopeptide of type I collagen (NTX) and serum osteocalcin (OC) were measured.

RESULTS

In Hartley guinea pigs, the number of chondrocytes in the surface layer started to decrease at 3 months. At 8 months, fibrillation expanded to the radial zone. In Weiser-Maple guinea pigs, no cartilage degeneration was noted even at 8 months. Subchondral bone plate thickness was significantly lower in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months. The subchondral bone had a rod-like and convex structure at 2 months in Hartley guinea pigs. BMD was significantly lower in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months. The serum OC level was significantly higher in Hartley guinea pigs than in Weiser-Maple guinea pigs at 2 months and 3 months, whereas the urinary NTX level was significantly lower in Hartley guinea pigs at 3 months.

CONCLUSION

Subchondral bone is fragile, and bone formation may be promoted in subchondral bone before the onset of cartilage degeneration in Hartley guinea pigs. Subchondral bone may be involved in the development of OA.

Oral ibandronate is as active as intravenous zoledronic acid for reducing bone turnover markers in women with breast cancer and bone metastases

BACKGROUND

Phase III study comparing the effect of oral ibandronate and intravenous zoledronic acid on bone markers.

PATIENTS AND METHODS

Breast cancer patients with bone metastases received ibandronate 50 mg/day (n = 137) or zoledronic acid 4 mg every 4 weeks (n = 138) for 12 weeks. The primary end point was mean percentage change in serum levels of cross-linked C-terminal telopeptide of type I collagen (S-CTX) at week 12. Urinary CTX (U-CTX), bone alkaline phosphatase (ALP), amino-terminal procollagen propeptide of type I collagen (PINP) and osteocalcin (OC) were also measured and bone pain and safety assessed.

RESULTS

Both bisphosphonates significantly reduced S-CTX (mean ibandronate 76% +/- 29 (SD) versus mean zoledronic acid 73% +/- 47; P < 0.001 for both versus baseline) and U-CTX (ibandronate 78% +/- 50 versus zoledronic acid 86% +/- 17; P < 0.001). The difference in S-CTX between treatments was 0.6% (confidence interval -1.7% to 3.0%), which was within the prespecified noninferiority margin. Bone ALP, PINP and OC decreased by 26%-47% compared with baseline with both bisphosphonates. Compared with zoledronic acid, ibandronate patients reported fewer adverse events overall (65.0% versus 75.9%), and on days 1-3 (8.0% versus 47.5%), including less pyrexia (overall incidence 0% versus 16.8%) and bone pain (5.8% versus 12.4%).

CONCLUSIONS

Oral ibandronate was well tolerated and statistically noninferior to zoledronic acid for percentage change in the bone resorption marker, S-CTX.

Soy isoflavones do not affect bone resorption in postmenopausal women: a dose-response study using a novel approach with 41Ca

INTRODUCTION

The purpose of this 3-way crossover study was to identify the effective dose of soy protein isolate enriched with isoflavones for suppressing bone resorption in postmenopausal women using a novel, rapid assessment of antibone resorbing treatments.

METHODS

Thirteen postmenopausal women (>or=6 yr since menopause) were predosed with 41Ca iv. After a 200-d baseline period, subjects were given 43 g soy protein/d that contained 0, 97.5, or 135.5 mg total isoflavones in randomized order. The soy protein isolate powder was incorporated into baked products and beverages. Each 50-d intervention phase was preceded by a 50-d pretreatment phase for comparison. Serum isoflavone levels and biochemical markers were measured at the end of each phase. Twenty-four-hour urine samples were collected approximately every 10 d during each phase for 41Ca/Ca analysis by accelerator mass spectrometry.

RESULTS

Serum isoflavone levels reflected the amount of isoflavones consumed in a dose-dependent manner. None of the isoflavone levels had a significant effect on biochemical markers of bone turnover, urinary cross-linked N teleopeptides of type I collagen and serum osteocalcin, or bone turnover as assessed by urinary 41Ca/Ca ratios.

CONCLUSIONS

Soy protein with isoflavone doses of up to 135.5 mg/d did not suppress bone resorption in postmenopausal women. This is the first efficacy trial using the novel technique of urinary 41Ca excretion from prelabeled bone.

Protective Effects of Sodium Daidzein Sulfonate on Trabecular Bone in Ovariectomized Rats

The ovariectomized (OVX) rat, as an established animal model of human osteoporosis, was adopted in the present experiment to study the protective effects of sodium daidzein sulfonate (SDS) on trabecular bone. Six-month-old Sprague-Dawley rats were sham-operated or ovariectomized. Five days later, the OVX rats were randomly assigned to one of three experimental groups and treated for 90 days with vehicle, 17beta-estradiol (E(2)) or SDS. Compared with OVX rats, SDS administration (15 mg/kg) prevented OVX-induced decrease in lumbar vertebral and femoral bone mineral density (BMD), and significantly increased bone mechanical strength parameters, including ultimate stress and elastic modulus. In the OVX group, the structure of trabecular plate in the femoral head was absorbed and became progressively thinner or was removed completely, accompanied by enlargement of marrow cavities and amalgamation of two or more marrow cavities. Administration of SDS and E(2 )prevented the change of trabecular bone microarchitecture induced by OVX, increasing the trabecular bone area and trabecular thickness, while decreasing the trabecular separation. These results indicate that SDS administration prevents OVX-induced decrease in BMD and bone mechanical strength, and has a moderate protective effect on the microarchitecture of trabecular bone in aged Sprague-Dawley rats.

Early bisphosphonate treatment in infants with severe osteogenesis imperfecta

OBJECTIVE

To evaluate prospectively the efficacy of bisphosphonate treatment in infants with severe forms of osteogenesis imperfecta (OI).

STUDY DESIGN

Of 10 children (6 females) with OI type III, 5 (group A) started treatment (2 mg/kg neridronate administered intravenously for 2 consecutive days, every 3 months) just after diagnosis at birth and 5 (group B) after 6 months. Ten untreated children, matched for sex, age, and clinical severity of OI, constituted a historical control group (group C). We measured weight, length, and number of fractures every 3 months and serum and urinary levels of calcium, phosphorus, creatinine, serum alkaline phosphatase, 25-hydroxyvitamin D, insulin-like growth factor I, parathyroid hormone, and osteocalcin, urinary type I collagen N-terminal telopeptide, and lateral radiography of vertebral column every 6 months.

RESULTS

Group A had better growth and a lower incidence of fractures than groups B and C in the first 6 months of treatment. In the second 6 months, both groups A and B had lower fracture rates than group C. After 12 months of therapy, osteocalcin and insulin-like growth factor I levels significantly increased only in group A. The urinary Ca/Cr ratio and N-terminal telopeptide/Cr ratio significantly declined only in treated patients. Vertebral body area and the structure of vertebral bodies improved in all treated patients, but especially in group A.

CONCLUSIONS

Cyclical neridronate treatment, started just after diagnosis at birth, had positive effects on growth and fracture rate.

Transgenic mice overexpressing macrophage migration inhibitory factor (MIF) exhibit high-turnover osteoporosis

The bone phenotype of mice overexpressing MIF was studied. These mice showed decreased trabecular bone, increased bone formation rate, and increased MMP-3, -9, and -13 mRNA expression in the femora and tibias. This model provides evidence of the role played by MIF in bone remodeling and balance in vivo.

INTRODUCTION

The role of macrophage migration inhibitory factor (MIF) in in vivo bone remodeling remains unelucidated. We describe disordered bone metabolism in transgenic mice overexpressing MIF.

MATERIALS AND METHODS

For in vivo study, muCT, bone histomorphometry, blood and urine biochemical data, and gene expression of MIF transgenic (MIF Tg) mice and littermate wildtype (WT) mice were examined. For in vitro study, osteoclastogenesis in the co-culture of bone marrow cells and osteoblasts from MIF Tg and WT were assessed.

RESULTS

muCT analyses revealed a significant reduction in the trabecular bone of distal femur in MIF Tg at 8-12 weeks of age. Histomorphometric analysis revealed increase in several measures of bone formation. Osteoclastogenesis was not influenced by the origin of bone marrow cells or osteoblasts. Urine level of deoxypyridinoline/creatinine and the mRNA levels of matrix metalloproteinase (MMP) -3, -9, and -13 in femurs were elevated in MIF Tg.

CONCLUSIONS

Overexpression of MIF causes high-turnover osteoporosis in mice. The increased expression of MMPs in bone was suggested, at least in part, as one cause of this phenotype, because MMPs plays important roles for bone resorption without affecting the formation of osteoclasts. This model provides evidence of the role played by MIF in bone remodeling and balance.

Acupuncture increases bone strength by improving mass and structure in established osteoporosis after ovariectomy in rats

The effects of acupuncture on bone biomechanical properties and histomorphometry in ovariectomized (OVX) rats were studied. Twenty-four 8-week-old female Sprague-Dawley rats were randomly assigned to three groups: sham, model and acupuncture. Rats in the model and acupuncture groups were ovariectomized, while those in the sham group underwent a sham operation. All rats were anesthetized and fastened for 15 minutes, and for the acupuncture group, needling on Pishu (BL20) and Shenshu (BL23) was performed. Blood and urine were collected to measure serum osteocalcin (OC) and urinary calcium, phosphorus or deoxypyridinoline (Dpd). After 16 weeks of treatment, all the rats were killed and their tibiae and femora were removed. The tibiae were used for analyses of bone histomorphometry and the femora for a three-point bending test. Acupuncture gave significant protection against ovariectomy-caused decline on femoral strength in the mechanical test, increased the trabecular bone volume and thickness, lowered the trabecular separation of tibiae and restricted the excretion of phosphorus and Dpd, while promoting the concentrations of serum osteocalcin as compared with model rats. These results seemed to indicate that acupuncture on the points of Pishu (BL20) and Shenshu (BL23) not only promoted the bone formation but also suppressed the bone resorption induced by OVX in osteoporotic rats, which suggests that it would be a potentially useful and convenient method in preventing osteoporosis.

Urinary CTX-II and glucosyl-galactosyl-pyridinoline are associated with the presence and severity of radiographic knee osteoarthritis in men

OBJECTIVE

To investigate the association between biochemical markers of bone, cartilage, and synovial turnover with the presence and severity of knee osteoarthritis (OA) in men.

METHODS

176 men aged 59-70 years from the MRC Hertfordshire Cohort were studied. Weightbearing anteroposterior and lateral semiflexed radiographs were taken of both knees. A lifestyle questionnaire including basic demographic details and a questionnaire detailing knee pain was completed. This random sample was stratified based on the Kellgren and Lawrence (K&L) score, and the following biochemical markers were analysed: serum osteocalcin, serum C-terminal crosslinked telopeptide of type I collagen (CTX-I), urinary C-terminal crosslinked telopeptide of type II collagen (CTX-II), and urinary glucosyl-galactosyl-pyridinoline (Glc-Gal-Pyd).

RESULTS

Age, body mass index (BMI), social class, smoking, and alcohol consumption were similar across K&L grades. Only one subject had a grade 4 K&L score, and was amalgamated with grade 3 subjects. A strong significant association was found between the presence of knee OA and urinary CTX-II and urinary Glc-Gal-Pyd (p=0.0001 and p=0.009), which persisted after adjustment for age and BMI. A significant positive association was also found between urinary CTX-II and urinary Glc-Gal-Pyd and the severity of K&L grade, joint space narrowing, and osteophytes scores, which persisted after adjustment for age and BMI. No associations between the presence and severity of knee OA were found for serum CTX-I or serum osteocalcin.

CONCLUSIONS

Urinary CTX-II and Glc-Gal-Pyd, but not systemic markers of bone turnover, are strongly associated with disease severity and the presence of OA at the tibiofemoral and patellofemoral joints in men.

[Metabolic causes of bone mineralisation disorders in patients with anorexia nervosa]

AIM

To assess the influence of metabolic disorders on densitometric parameters in patients with anorexia nervosa.

MATERIAL AND METHODS

Thirty patients with diagnosis of anorexia nervosa and twenty six healthy females from control group participated in the study. Serum calcium, phosphorus, estradiol, cortisol, osteocalcin and C-terminal telopeptide of collagen type I concentrations were estimated. Urine sample was analysed for 24 hrs excretion of calcium and phosphorus. Lumbar bone mineral density and Z-score were assessed by DEXA.

RESULTS

Statistical analysis showed the presence of positive correlation between densitometric parameters and serum concentrations of estradiol and phosphorus and negative correlation with serum concentration of cortisol. The duration of anorexia nervosa and secondary amenorrhea correlated negatively with densitometric parameters. There was no correlation between bone turnover markers and densitometric parameters.

CONCLUSIONS

Current data are in agreement with hypothesis of multifactorial ethiopathogenesis of osteoporosis in anorexia nervosa.

Clinical and Biologic Factors Related to Oral Implant Failure: A 2-Year Follow-Up Study

The purpose of this study is to evaluate urinary biomarkers of bone formation and resorption as predictive factors for oral implant failure, and to contribute to the knowledge of factors related to oral implant failure. A total of 93 patients between 18 and 85 years old, with an indication of oral implant, were eligible in this 2-year prospective, open, and nonrandomized study. Patients who had bone graft before implantation or presented with prosthetic difficulties (implant-to-crown ratio < 1, and/or unfavorable intermaxillary space) were excluded. All patients received either Frialit-2 (Friadent, Mannheim, Germany), cylinder, or screwed implants or IMZ Twin Plus (Friadent), cylinder implants, with FRIOS (Friadent) titanium coating. Serum osteocalcin, and urinary pyridinoline and deoxypyridinoline were measured, together with bone density at implant location. The primary endpoint (implant failure) was the implant removal (radiographic evidence of peri-implant bone loss and/or pockets). Factors related to implant failure were analyzed using multilevel logistic regression models to consider within-patient effects. Of the 93 patients included, 61% were female, and 16% were current smokers. A total of 266 oral implants were placed and analyzed, with a mean number of 3.1 implants by patient. Eleven and 15% of bone locations scored at D1 and D4, respectively, for the Misch bone density scoring. The majority of implants (72%) were placed more than 3 months after tooth extraction, using a Frialit-2 system in 73% of cases. The mean of osteocalcin was 17.3 (+/-9.4) ng/L; those of pyridinoline and deoxypyridinoline were 33.2 (+/-15.8) and 10.2 (+/-11.9) mmol per creatinine mmol, respectively. At one-year, 95.5% (95% confidence interval 92.5-97.5) of implants have not been removed. One year later, no further implant failed. In both univariate and multivariate analysis, osteocalcin, pyridinoline, and deoxypyridinoline were not significant predictive factors of oral implant failure. In multilevel logistic regression analysis, only tobacco consumption and single-tooth replacement or removable prosthesis were independent and significant predictive factors of oral implant failure. Serum osteocalcin, and urinary pyridinoline and deoxypyridinoline were not predictive of oral implant failure in this study. These results suggest that oral implants are more likely to fail for posterior single-tooth replacements and removable prostheses rather than for complete edentulous fixed bridgeworks or overdentures. Tobacco smoking has been identified as a major risk factor of oral implant failure.

Urinary osteocalcin as a marker of bone metabolism

BACKGROUND

Osteocalcin (OC) is produced by osteoblasts during bone formation, and circulating OC has been used in clinical investigations as a marker of bone metabolism. OC is excreted into urine by glomerular filtration and can be found in urine as midmolecule fragments.

METHODS

We developed and evaluated three immunoassays (U-MidOC, U-LongOC, and U-TotalOC) for the detection of various molecular forms of urine OC (U-OC). We evaluated the association of U-OC with other markers of bone turnover and with bone mass in 1044 elderly women and studied seasonal and circadian variation of U-OC.

RESULTS

U-OC correlated with other bone turnover markers [Spearman correlation (r), 0.30-0.57; P <0.0001], demonstrating the association between U-OC and skeletal metabolism. There was also a significant association between bone metabolism assessed by U-OC quartiles and bone mass assessed by total body bone mineral content (P <0.0001). The seasonal effects appeared to be rather small, but we observed a significant circadian rhythm similar to the one reported for serum OC with high values in the morning and low values in the afternoon.

CONCLUSIONS

The three immunoassays had unique specificities toward different naturally occurring U-OC fragments. U-OC concentrations measured with any of these assays correlated with bone turnover rates assessed by conventional serum markers of bone metabolism. The measurement of OC in urine samples could be used as an index of bone turnover in monitoring bone metabolism.

Fracture-induced changes in bone turnover: a potential confounder in the use of biochemical markers in osteoporosis

To examine the short- and long-term bone metabolic effects of fracture assessed by biochemical markers, we utilized a clinical fracture model-proximal tibial osteotomy-and prospectively followed 14 patients. This model of an induced fracture of a major bone gives the advantage of assessing baseline levels prior to fracture. Follow-up occurred at 6-9 weeks, 4-7 months, 9-13 months, and 14-17 months after fracture. Serum was assayed for type 1 procollagen peptide (PICP), total alkaline phosphatase (ALP), and carboxy-terminal-telopeptide of type I collagen (ICTP), while deoxypyridinoline (Dpyr) was measured in urine. Serum osteocalcin (OC) was measured using two recently developed two-site immunofluorometric assays, which both measure full-length and fragmented forms of OC (OCtot), with one of the assays specifically detecting only the carboxylated form of OC (OCcxy). In addition, OC was measured in urine using the same assays as those used for serum. Serum OCtot increased to a peak at 4-7 months after fracture (P < 0.001) and a similar increase was seen for OCcxy (P < 0.05) and ALP (P < 0.01). Bone formation had returned to baseline after a year. Dpyr increased significantly, with a doubling at 6 weeks, while serum (S)-ICTP increased by 73% (P < 0.01 and P < 0.001). Urine OC increased to a maximum of 84% at 6 weeks. The initial percentage increase of bone resorption was greater than that of bone formation. We conclude that: (1) bone turnover as measured by biochemical markers is altered soon after fracture, (2) the major changes occur within 6 weeks to 6 months, but may persist for up to a year. (3) The initial increase in bone resorption exceeds the increase in bone formation, which may contribute to the enhanced bone loss after fracture. (4) The two novel urine OC assays show a similar pattern of change as established marks of bone resorption, which may indicate that they measure bone resorption. (5) Fracture-induced effects on bone turnover are significant and, thus, are potential confounders in the assessment of osteoporosis.

Bone resorption activity of osteolytic metastatic lung and breast cancers

Production of bone resorption mediators and bone resorption activity were compared among osteolytic metastatic cancers, normal bone tissues, and soft tissue metastatic cancers to search for the possible factors leading to cancer-induced bone resorption. Twenty-five patients with untreated osteolytic metastatic breast or non-small cell lung cancers consisted of the study group. Normal bone tissues obtained from the same patient were used as internal controls; and tumor tissues from patients with soft tissue metastasis were used as external controls. Serum and urinary bone turnover markers were measured. Tissues harvested during surgery were subjected to tissue culture. The levels of prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) in the supernatant after 72 h of culture were measured. Bone resorption activity was measured by calcium release from cultured calvarias, and bone volume as well as osteoclast number in bone sections. Patients with osteolytic metastatic cancers showed significantly decreased serum osteocalcin, increased serum alkaline phosphatase, and urinary deoxypyridinoline levels. Osteolytic metastatic cancers produced significantly more PGE2 than both controls. Conditioned medium from osteolytic metastatic tumors showed significantly enhanced bone resorption activity, and indomethacin significantly reduced this activity. Levels of PGE2, and bone resorption activity increased in osteolytic tumor tissues than soft tissue metastatic tissues in the same patient indicated that the same tumor cells might respond differently to different microenvironments. Our observation showed that PGE2 was produced by osteolytic metastatic cancers and stimulated bone resorption in mice calvarias. PGE2 inhibitor may be applicable in reducing bone resorption by osteolytic metastatic cancers.

Bone remodelation markers are useful in the management of monoclonal gammopathies

The evaluation of bone disease in multiple myeloma (MM) by conventional radiology has low reproducibility. In the last decade, several serum and urine biochemical parameters, for evaluation of bone turnover, have become available. The present study was designed to explore the value of six bone remodelation markers. It was studied in a series of 176 newly diagnosed patients with monoclonal gammopathies (107 MM and 69 monoclonal gammopathies of unknown significance (MGUS)). As control groups we used 25 patients with benign osteoporosis (BO) and 32 healthy individuals (HI). The bone markers analyzed included: bone resorption markers (BRM) (total pyridinoline, total deoxypyridinoline, free deoxypyridinoline and C-terminal telopeptide of collagen I) and bone formation markers (BFM) (bone alkaline phosphatase (bAP) and osteocalcin (OC)). Serum or urinary levels of BRM were significantly higher in MM patients than in MGUS patients, BO patients or HI (P < 0.001, respectively). BRM were higher in MM patients with lytic lesions. However, only C-terminal telopeptide discriminated MM patients without bone lesions from MGUS patients. BFM did not show significant differences in the aforementioned comparisons, although a trend toward higher values of OC and lower values of bAP in patients with early bone affectation was observed. Ratios BRM/BFM that contained bAP exhibited differences that were most significant between the MM group and other entities, as well as between the different MM subgroups. In fact, the ratios BRM/bAP provided discrimination between the MM subgroup without lyses and MGUS group (P < 0.01). BRM and BFM, especially the ratios, are useful in the evaluation of bone lesions in patients with monoclonal gammopathies.

Characterization of aged osteocalcin fragments derived from bone resorption

INTRODUCTION

Osteocalcin (OC) is a small bone matrix protein exclusively found in mineralized tissue. OC measured in serum or plasma provides an index of bone formation. In the present study a sensitive inhibition ELISA was established that could quantify fragments derived from the OC Mid-region in human urine.

METHODS

The ELISA was based on a monoclonal antibody directed against residues 21-29 of human OC (Mid-OC Urine ELISA). OC fragments were isolated from human urine by immunoaffinity chromatography. OC fragments were purified further by reversed phase high performance chromatography for characterization by N-terminal sequencing and mass-spectrometry. OC fragments were assayed in bone cell culture supernatants and in serum and urine from patients undergoing anti-resorptive bisphosphonate therapy using the Mid-OC urine ELISA.

RESULTS AND CONCLUSION

It was demonstrated that the release of OC fragments was highly correlated with osteoclast-mediated pit formation (r2= 0.89) and with an established marker of bone resorption (CTX; r2=0.91). Mid-OC values were decreased markedly after 3 and 10 days of anti-resorptive bisphosphonate treatment further indicating that the marker reflects bone resorption. The molecular characterization revealed that most of these molecules were less than 15 amino acids in length and many contained modified aspartyl residues (D-aspartyl and isoaspartyl) characteristic of aged proteins. The presence of such modifications shows that these molecules have resided in the bone matrix for an extended period and thus they cannot be derived directly from bone formation. In conclusion, these findings demonstrate that OC-fragments are released during osteoclastic bone resorption and that the quantification of specific age-modified OC fragments can provide an index of bone resorption.

Effect of systemic glucocorticoid therapy on bone metabolism and the osteoprotegerin system in patients with active Crohn's disease

BACKGROUND AND AIMS

Osteoporosis may occur in 25-30% of patients with Crohn's disease. Its pathogenesis is not completely understood. Both systemic inflammation in acute disease and treatment with systemic glucocorticoids have been implicated. The aim of the present study was to investigate changes in bone density and biochemical markers of bone metabolism before and during a 3-month period of high-dose glucocorticoid treatment for acute flare-up of Crohn's disease.

METHODS

Twenty-five patients with active Crohn's disease requiring systemic glucocorticoid treatment (prednisolone, 60 mg/day) were investigated. Lumbar spine and femoral neck bone mineral densitometry was performed at baseline and again after 3 months. Clinical examinations including evaluation of the Crohn's disease activity index and measurement of the biochemical markers osteocalcin, deoxypyridinoline, osteoprotegerin and the soluble receptor activator of NF-kappaB ligand were performed prior to, and at 1, 2 and 12 weeks following steroid administration. RESULTS Median lumbar bone mineral density decreased significantly during the observation period by 1.04% from -0.84 (t score; range, -2.8 to +0.57) to -0.95 (range, -3.1 to +0.40; P = 0.022), while bone density of the total femur decreased by 2.9% from -0.83 (range, -2.61 to +1.86) to -0.90 (range, -2.65 to +0.19; P = 0.01). Serum levels of osteocalcin, a bone formation marker, and osteoprotegerin, an anti-resorptive cytokine produced by osteoblasts, decreased after the first 2 weeks of treatment and reached baseline levels after 3 months. No significant change was found for the bone resorption marker deoxypyridinoline, while soluble receptor activator of NF-kappaB ligand, a cytokine promoting bone resorption, tended to increase during steroid treatment.

CONCLUSION

A decrease in bone mineral density in patients with Crohn's disease appears to result, at least in part, from a short-term effect of systemic glucocorticoid. Modulation of osteoclastogenesis by the receptor activator of NF-kappaB ligand/osteoprotegerin cytokine system and decreased osteoblastic function may be the underlying molecular basis.

Identification of novel proteolytic forms of osteocalcin in human urine

In this study, we report the isolation and characterization of osteocalcin in human urine using mass spectrometry and N-terminal sequencing. Multiple proteolytic forms of osteocalcin were found, which consisted of 16-27 residues from the middle region of the molecule. Several fragments had residue Gly7 at the N-terminus and the most predominant was fragment 7-31. Additional fragments starting from residue Asp14 were detected in the samples of children and young adults. Immunochemical detection of urine osteocalcin fragments had a statistically significant negative correlation to bone mineral density in evaluation of urine samples from 75-year-old women. Thus, the measurement of osteocalcin fragments in urine may have potential applications in diagnostics related to disorders of bone metabolism.

Alendronate daily, weekly in conventional tablets and weekly in enteric tablets: preliminary study on the effects in bone turnover markers and incidence of side effects

Bisphosphonates are now in the vanguard of osteoporosis treatment. Frequently, gastro-oesophageal symptoms are associated with these drugs. The objective of this study was to compare side effects and bone turnover markers in postmenopausal women who had received alendronate daily or weekly in tablets with or without enteric coating. We conducted a randomised, double-blind, 3-month trial. The trial involved 75 volunteers, aged 45-58 with moderate to severe osteopenia (T-score lower than -2 SD) assessed by quantitative ultrasound. Women were assigned randomly to receive: (a) alendronate 10mg/day: (b) alendronate 70 mg once a week: or (c) enteric alendronate 70 mg per week. We recorded side effects, C-telopeptide, osteocalcin and urine hydroxyproline at the start of the study and at 3 months. After 3 months, pyrosis (heartburn) was noted by seven women in group A (28%), three in group B (12%) and two in group C (8%); nausea: by one woman in group B; and headache by one patient in each group. C-telopeptide (A: 40.7%; B: 34.1% and C: 38.5%); hydroxyproline (A: 31.1%;B: 25.3% and C: 31.5%) and osteocalcin (A: 27.0%; B: 25.4% and C: 25.1%) decreased similarly in the three groups. Weekly intake of alendronate, whether conventional or enteric-coated; is associated with less heartburn and nausea. Enteric alendronate has a similar action to the conventional tablets on biochemical markers.

Bone remodelling in osteoarthrosic subjects undergoing a physical exercise program

BACKGROUND

The connection between osteoarthritis (OA) and osteoporosis (OP) has attracted considerable attention but reports about bone mass density (BMD) in OA are often contradictory. Some data indicate that BMD is higher in OA patients than in healthy subjects, whereas other studies showed no differences. It has been observed that mud pack treatment (MPT) induces a decrease in cytokines with bone-resorbing effects. The aim of this study is to evaluate the response of bone and connective tissue to physical exercise and thermal treatment.

METHODS

Forty osteoarthrosic patients were divided in group A (physical exercise and MPT), and group B (physical exercise alone). Blood and urine samples were collected before and after the treatments to assay blood metabolic markers and urinary hydroxyproline.

RESULTS

In group A, some parameters show statistically significant differences before and after mud pack treatment (MPT). In group B, all parameters present no statistical significant changes before and after the physical exercise program.

CONCLUSIONS

Few studies established the importance of exercise to maintain normal cartilage and bone metabolism. In group A of the present study, an influence on all the parameters of bone metabolism is evident. It is possible that physical exercise only if combined with MPT stimulates physiologic bone metabolism and favors skeletal health.

A urine midmolecule osteocalcin assay shows higher discriminatory power than a serum midmolecule osteocalcin assay during short-term alendronate treatment of osteoporotic patients

We isolated and characterized a peptide fragment corresponding to amino acid sequence 14-28 of human osteocalcin in urine from Paget's disease, and developed a polyclonal antibody reactive to this peptide in urine. We used this antibody to measure urinary fragments of osteocalcin and compared to efficacy of the urinary osteocalcin assay with a serum osteocalcin (sOC) assay (ELISA-Osteo, Cis-Bio International) to monitor the short-term changes in bone turnover in response to alendronate treatment. The synthetic peptide-based urinary osteocalcin (uOC) radioimmunoassay (RIA) showed an analytical sensitivity of 6.25 ng/mL, standard curve range of 3.12-400 ng/mL, and mean intra- (n = 20) and interassay (n = 30) coefficient of variation (CV) of <15%. Urine osteocalcin concentrations in postmenopausal osteoporotic patients were approximately 90% higher than in normal premenopausal controls. Series of 24 h urine and matched serum samples were collected at baseline, 30 days, and 90 days after treatment of postmenopausal osteoporotic patients with daily dose of 10 mg alendronate. We measured urinary osteocalcin (uOc) levels and urinary N-telopeptide (uNTx, Ostex) in urine samples and serum N-telopeptide (sNTx), C-telopeptide (sCTx, Osteometer), serum osteocalcin (sOC) as well as bone-specific alkaline phosphatase (sALP) (Alkphose-B, Metra Biosystems) in serum samples. The percent change data obtained between baseline and 30 days (n = 18) posttreatment suggested a rapid decline in uOC concentration (-27%, p < 0.01) in response to alendronate treatment, as compared with a marginal and nonsignificant decrease in sOC (-7.2%, p = 0.417) or sALP (-3.4%, p = 0.689), two specific markers of bone formation. As expected, due to the coupling of bone formation and bone resorption, the concentration of all markers showed a 30%-45% decline compared with baseline values after 90 days (n = 16) of treatment. Correlation of markers after a 30 day treatment with alendronate revealed a higher correlation (r = 0.61, p < 0.01) between uOC and uNTx, as compared with sOC (r = 0.03, p = 0.447) or sALP (r = -0.14, p = 0.295) with uNTx. Similarly, correlation coefficients with r values between 0.48 and 0.55 (p < 0.05) were observed between uOC, sNTx, and sCTx, whereas no significant correlation was observed between sOC and sNTx or sCTx. These results provide indirect evidence that fragments measured by the urine assay probably originated from bone resorption, and suggest that the uOC assay could be used to assess short-term changes in bone metabolism with regard to osteocalcin.

Implant design affects markers of bone resorption and formation in total hip replacement

Concentrations of the bone resorption markers pyridinoline and deoxypyridinoline and the bone formation marker osteocalcin were measured in 24-h urine collections from 30 subjects who underwent unilateral total hip replacements for monoarticular symptomatic osteoarthrosis and 10 controls. The patient groups were divided based on the femoral implant type (cemented cobalt alloy stem, cementless porous coated cobalt alloy stem, and cementless porous coated titanium alloy stem). Urine collections were performed before surgery and then at 3, 6, 12, 24, and 36 months. There were significant changes over time in the three patient groups for pyridinoline, deoxypyridinoline, and the ratio of osteocalcin to deoxypyridinoline (p < or = 0.01), but the control group values did not change over time. The resorption markers tended to peak at 3 months and the osteocalcin to deoxypyridinoline ratio was more variable, having depressed values in the cementless cobalt alloy group and elevated values in the other two groups compared with baseline. The cementless cobalt alloy group had higher resorption marker levels than the cemented cobalt alloy group at 6, 12, 24, and 36 months and higher levels than the cementless titanium alloy group at all postoperative times (p < 0.05). The osteocalcin to deoxypyridinoline ratio was lower in the cementless cobalt alloy group than in the cemented cobalt alloy group at 3, 6, and 24 months and the cementless titanium alloy group at 6, 12, and 24 months (p < 0.05). For the cemented cobalt chrome group, the baseline-normalized resorption marker values at 3 months and 6 months were correlated with the severity of radiographically assessed bone loss at 36 months (0.749 < r < 0.840; p < 0.05). For the cementless titanium alloy group, baseline-normalized osteocalcin/ deoxypyridinoline ratios at 3 months and 6 months were related inversely to radiographic bone loss at 36 months (0.687 < r < 0.749; p < 0.05). Thus, body fluid markers of bone metabolism change after total hip replacement. In addition, the changes in the marker concentrations were sensitive to implant design and were correlated with subsequent stress-shielding-induced bone loss.

Markers of bone turnover in postmenopausal women receiving hormone replacement therapy

We investigated the effects of hormone replacement therapy (n = 27) on biochemical markers of bone turnover in a cross-sectional study of 127 postmenopausal women (according to WHO guidelines 18 patients had normal bone mineral density and 109 suffered from bone loss). Urinary excretion of free deoxypyridinoline and C- or N-telopeptide fragments of type I collagen served as bone resorption markers, serum osteocalcin as a bone formation marker. In women with no hormone replacement therapy, only C- and N-telopeptides correlated significantly with the lumbal T-score as an index for bone mineral density. Patients with bone loss receiving hormone replacement therapy exhibited significantly lower C-telopeptide, N-telopeptide and osteocalcin levels than those with no therapy (mean -45%, -43% and -26%, respectively), while deoxypyridinoline showed no significant differences. Among the markers investigated, C- and N-telopeptides seemed to be more reliable to detect therapeutic effects on bone metabolism. We present a preliminary model to evaluate bone turnover and resorption/formation rate.

Biochemical markers in menopausal women

Markers of bone formation (osteocalcin and C-Terminal Propeptide of Type I Collagen [CICP]) and of resorption (Crosslaps, total pyridinoline [Pyd] and deoxypyridinoline [Dpd]) as well as female sex hormones (estradiol [E2], follicle stimulating hormone [FSH] and luteinizing hormone [LH]) were measured in 237 women aged 44-66 years coming for the first medical examination to the outpatient clinic of menopause at the Kaiser-Franz-Josef-Hospital, Vienna. All women (0.5-5.0 years since cessation of menses) selected were not taking medications other than hormone replacement therapy in 52 cases (21.9%) and did not have diseases known to affect bone and mineral metabolism. The best correlation was found between Dpd and Pyd (r = 0.63, p = 0.0001), followed by Crosslaps and Dpd (r = 0.47, p = 0.0001). Only weak but significant correlations between E2 and Crosslaps (r = 0.21, p < 0.0001) as well as E2 and osteocalcin (r = 0.16, p = 0.0007) were observed, 53% of the 237 women suffered from a severe E2 deficiency (E2 < 10.0 ng/L). In these patients Crosslaps (approx. +48%) and osteocalcin (+22%) were significantly higher (p < 0.0001) compared to those with E2 concentrations > 10 ng/L. Women with E2 concentrations > 10 ng/L were further subdivided into women with and without sex hormone replacement therapy, whereby no statistical differences in any of the biochemical markers could be observed between these both groups. In conclusion, we could clearly demonstrate that in postmenopausal women suffering from severe E2 deficiency (E2 < 10 ng/L) Crosslaps and osteocalcin are significantly increased, indicating in principle a clear correlation between E2 deficiency and these markers of bone turnover.

Long-term retention of injected barium-133 in man

Data are presented on the whole-body retention of 133Ba (half-life 10.74 y), over periods of up to 13 y after injection into six healthy male volunteers aged 25-81, and on their levels of biochemical markers for bone turnover. The results are relevant to propositions underlying the ICRP's current (Publication 67) and former (Publication 20) models of alkaline earth metabolism. The tracer was predominantly skeletal within weeks of the injection, as predicted in the current model. The mean retention accorded satisfactorily throughout with predictions based on the current model, but this accord does not necessarily validate the model, for two reasons. First, parameter values attributed to barium were influenced by data emerging during the early years of this study. Second, bone resorption rates in these subjects, as indicated by urinary markers, appear insufficient to explain the long-term reductions in skeletal retention which, in the present model, arise exclusively through this mechanism.

Effect of pamidronate administration on markers of bone turnover and disease activity in multiple myeloma

AIM

Bisphosphonates are potent inhibitors of osteoclastic activity and are used in the treatment of multiple myeloma (MM) in combination with chemotherapy. The effect of pamidronate on markers of bone resorption [cross-linked N-telopeptides of type I collagen (NTx)], markers of bone formation [serum alkaline phosphatase (BAP) and osteocalcin (OSC)], interleukin-6 (IL-6), beta2-microglobulin, CRP, paraprotein and disease-related pain and skeletal events has been evaluated in 62 newly diagnosed patients with MM.

PATIENTS AND METHODS

The patients were randomly assigned to two groups: the first included 32 patients under chemotherapy and pamidronate (group I) and the second 30 patients on chemotherapy only (group II). Pamidronate was administered at a monthly dose of 90 mg iv, and the above parameters were evaluated at the beginning of this study and after 1, 3, 6, 9, 12 and 14 months of treatment.

RESULTS

The addition of pamidronate to chemotherapy resulted in a significant reduction of NTx, IL-6 and paraprotein from the 3rd month and of beta2-microglobulin, CRP and pain from the 6th month of treatment. No changes of NTx, IL-6, beta2-microglobulin, CRP or skeletal events were observed in patients of group II, while paraprotein was significantly reduced after 6 months of treatment. The differences in NTx, IL-6, paraprotein and beta2-microglobulin were statistically significant between the two groups. Multivariate analysis revealed a significant correlation between changes of NTx, changes of IL-6 in both groups and reduction of pain and paraprotein in group I.

CONCLUSIONS

These results suggest that pamidronate may have a synergistic action with chemotherapy in decreasing osteoclastic activity, in reducing markers of myeloma activity and myeloma related pain and in improving the quality of life in patients with MM.

Space flight is associated with rapid decreases of undercarboxylated osteocalcin and increases of markers of bone resorption without changes in their circadian variation: observations in two cosmonauts

BACKGROUND

Microgravity induces bone loss by mechanism(s) that remain largely unknown.

METHODS

We measured biochemical markers related to bone remodeling in two cosmonauts before, during, and after 21- and 180-day space flights, respectively.

RESULTS

During both flights, type I procollagen propeptide and bone alkaline phosphatase decreased as early as 8 days after launch. Undercarboxylated osteocalcin percentage increased early and remained high during both flights. Vitamin K supplementation restored carboxylation of osteocalcin during the long-term flight. Urinary and serum C-telopeptide of type I collagen (CTX) increased as early as day 8 of the flights; the increase was greater in serum than in urine. Pyridinoline, free deoxypyridinoline, and N-telopeptide increased less than CTX during the short-term space flight. The circadian rhythm of bone resorption assessed by urine CTX and free deoxypyridinoline was not altered by microgravity.

CONCLUSION

Vitamin K metabolism or action and bone remodeling may be altered in cosmonauts.

Bone mineral density and bone turnover in patients with knee osteoarthritis compared with generalized osteoarthritis

The aim of this study was to investigate bone mineral density (BMD) and bone turnover in patients with primary knee osteoarthritis (KOA) and to compare them with generalized OA (GOA) and nonGOA patients. A total of 88 postmenopausal primary KOA patients were studied. OA was graded by using knee radiographs. BMD of the lumber spine, femur, and radius, and biochemical markers of bone turnover, pyridinoline (Pyr), deoxypyridinoline (Dpyr), CTx, and osteocalcin were compared among each grade. BMD was also compared with 88 normal controls who were age and weight-matched. In 88 KOA patients, 56 were divided into 28 GOA and 28 non-GOA groups by grading hand radiographs. BMD and biochemical markers were compared between GOA and non-GOA. KOA patients had higher BMD at several skeletal sites compared with age- and weight-matched normals. A significant difference of BMD between each grade was observed between grades 0-1 and 3 (0.774+/-0.143 versus 0.940+/-0.185 g/cm(2), P<0.001), grades 2 and 3 (0.781+/-0.125 versus 0.940+/-0.185 g/cm(2), P<0.01) in the spine, and between grades 0-1 and 3 (0.505+/-0.100 versus 0.564+/-0.127 g/cm(2), P<0.05) in the trochanter. A significant difference of biochemical bone markers was observed between grades 0-1 and 3 (P<0.05) and between grades 2 and 3 (P<0.05) in Pyr and grades 0-1 and 3 (P<0.05) and between grades 1 and 4 (P<0.05) in Dpyr, but not in osteocalcin and CTx. GOA patients had higher BMD of the spine (0.902+/-0.175 versus 0.747+/-0.138 g/cm(2), P<0.01), trochanter (0.535+/-0.107 versus 0.480+/-0.107 g/cm(2), P<0.05), and one-third of the radius (0.526+/-0.068 versus 0.472+/-0. 089 g/cm(2), P<0.05) and had significantly higher biochemical markers in Pyr and Dpyr than non-GOA patients. It is concluded that KOA patients had higher BMD at several skeletal sites. Biochemical bone markers were influenced by some degree of cartilage damage in OA patients. This tendency was stronger in GOA patients than in non-GOA patients.

Evaluation of bone and collagen metabolism by assessing urinary biomarkers in non-human primates

The purpose of this investigation was to evaluate mineralized and non-mineralized connective tissue responses of non-human primates to microgravity by non-invasive analysis of urinary biomarkers.

Short-term risedronate treatment in postmenopausal women: effects on biochemical markers of bone turnover

The development of new biochemical markers has made it possible to assess the effects of therapeutic agents on bone turnover more rapidly and precisely. In this early phase II study, we analyzed the effects of short-term, high-dose treatment with risedronate, a potent pyridinyl bisphosphonate, on markers of bone resorption and formation. Resorption markers included urinary free deoxypyridinoline (D-Pyr) crosslinks, N-terminal telopeptide (NTx) and C-terminal telopeptide (CTx) type I collagen crosslinks. Bone formation markers included osteocalcin (OC), bone-specific alkaline phosphatase (BSAP) and the C-terminal peptide of type I procollagen (PICP). All three resorption markers showed rapid, significant (p<0.05) decreases from baseline following daily administration of 30 mg risedronate for 2 weeks. The mean decreases at 2 weeks were 28% for D-Pyr, 61% for NTx and 73% for CTx, respectively. Over the next 10 weeks after treatment, D-Pyr approached baseline while NTx and CTx remained well below baseline values. The markers of bone formation showed little change during therapy but decreased significantly at 4-10 weeks after therapy - an expected outcome of bisphosphonate therapy. Moreover, there was a significant correlation between the early effects on bone resorption markers and the delayed effects on formation markers. This study demonstrates that the approved dose of risedonate (30 mg/day) for Paget's disease is effective at decreasing bone turnover after 2 weeks of treatment, as observed by the sensitive response of bone turnover markers.

Response of vitamin K status to different intakes and sources of phylloquinone-rich foods: comparison of younger and older adults

BACKGROUND

Phylloquinone, found in dark-green vegetables and certain plant oils, is the primary dietary source of the fat-soluble vitamin K. Limited data suggest that the relative bioavailability of phylloquinone from vegetables is lower than that from a supplement. This finding is relevant to the maintenance of optimal vitamin K status.

OBJECTIVE

The objective of this study was to compare, in younger and older adults, the relative bioavailability of phylloquinone from a vegetable with that of a fortified oil.

DESIGN

In a crossover design with three 15-d residency periods in a metabolic unit, younger and older men and women (n = 36) consumed a mixed diet containing 100 microg phylloquinone/d. During 2 residency periods, the mixed diet was supplemented for 5 d with either broccoli (377 microg phylloquinone/d; broccoli diet) or phylloquinone-fortified oil (417 microg/d; oil diet). The relative bioavailability of phylloquinone was defined by the difference in plasma phylloquinone, percentage serum undercarboxylated osteocalcin (%ucOC), and urinary gamma-carboxyglutamic acid in response to 5 d of supplementation.

RESULTS

For both younger and older adults, plasma phylloquinone concentrations were higher (P < 0.001) and %ucOC values were lower (P = 0.001) after the broccoli and oil diets than after the mixed diet only. Overall, the response to broccoli supplementation was not significantly different from the response to the fortified oil in either age group. Urinary gamma-carboxyglutamic acid did not change in response to supplementation.

CONCLUSIONS

There was no significant difference in the relative bioavailability of phylloquinone, as evidenced by the lack of a significant difference in plasma phylloquinone and %ucOC between the 2 groups after either the broccoli or oil diets for younger and older adults.

Determinants of the first decade of bone loss after menopause at spine, hip and radius

This study documented bone loss at three different sites in the early postmenopausal period, and examined potential predictors. Forty-three women underwent repeated measurements of bone density at the lumbar spine, proximal femur and distal radius for up to 14 years. Individual rates of bone loss were calculated for the spine and hip; for radial trabecular bone, rates were calculated separately for two time periods, earlier and later after menopause. In the spine and radius, initially high rates of loss diminished with time after menopause. No positive correlations for bone loss were found between the three sites, suggesting that faster than average bone loss was specific to individual bones. High body mass index (BMI) was significantly protective against fast bone loss at the spine and radius; in the spine, each unit increase in BMI was associated with a approximately 5% reduction in the rate of bone loss. Of the other variables measured (maximum oxygen consumption, lean body mass, fat mass, mean psoas muscle area at the L3 level, hand grip strength as well as anthropometry) only bone densitometry was sufficiently predictive to help guidance on hormone replacement or other prophylactic therapy. The data suggest that the known relationship between excessive leanness and risk of osteoporosis and vertebral fracture after menopause might in part be due to fast post-menopausal bone loss. Because bulk of psoas muscle was associated with low spine loss rates, the data also support a role for applied muscular loading in local maintenance of bone density.

Hormone replacement therapy in perimenopause: effect of a low dose oral contraceptive preparation on bone quantitative ultrasound characteristics

OBJECTIVES

Our aim was to assess the effects of a combined oral contraceptive (OC) preparation on bone quantitative ultrasound and biochemical markers of bone metabolism in perimenopausal women.

DESIGN

Bone biochemical markers and bone quantitative ultrasound were evaluated in a longitudinal 2-year follow-up study conducted in healthy, normally menstruating perimenopausal women, perimenopausal oligomenorrheic women, and age-matched oral contraceptive-treated women (20 micrograms of ethinyl estradiol plus 0.15 mg desogestrel). The results were analyzed by factorial or repeated-measures analysis of variance, as appropriate.

RESULTS

In normal women, there were no significant modifications in menstrual cycle, plasma FSH and estradiol levels, biochemical markers of bone turnover, and bone quantitative ultrasound. Conversely, in oligomenorrheic women, an increase in the cycle length with a concomitant rise in circulating plasma FSH and parallel decrease of plasma estradiol levels was evident. In this group, an increase in both urinary excretion of hydroxyproline and plasma osteocalcin levels paralleled a decrease in bone quantitative ultrasound. In perimenopausal OC-treated women, the pattern of osteocalcin and urinary excretion of hydroxyproline showed a slight decrease, whereas bone quantitative ultrasound did not show any significant modification.

CONCLUSION

Perimenopausal OC administration can prevent the increase in bone turnover and the decrease in bone quantitative ultrasound that follow the perimenopausal impairment of ovarian function.

Acute fasting diminishes the circadian rhythm of biochemical markers of bone resorption

OBJECTIVE

Biochemical markers of bone turnover exhibit circadian rhythms with the peak during the night/early morning and the nadir in the late afternoon. The nocturnal increase in bone resorption could theoretically be caused by the absence of food consumption which brings about a decrease in net calcium absorption and an increase in parathyroid hormone (PTH), followed by increased bone resorption in response to the body's demand for calcium. The aim of the present study was to assess the influence of a 33-h fast on the circadian variation in biochemical markers of bone turnover.

DESIGN

Eleven healthy premenopausal women (age: 24+/-5 years) participated in a randomised, cross-over study consisting of two periods: either 33h of fasting (fasting) followed 1 week later by a 33-h period with regular meals eaten at 0800-0830h, 1130-1230h and 1800-1900h (control) or vice versa.

METHODS

Urinary CrossLaps (U-CL/Cr) corrected with creatinine, as a marker of bone resorption; serum osteocalcin (sOC) as a marker of bone formation; serum intact PTH (iPTH); serum phosphate; and serum calcium corrected with albumin.

RESULTS

Both the fasting and the control periods showed a significant circadian rhythm in U-CL/Cr (P<0.001), but the decrease was significantly less pronounced in the morning hours during the fasting period. Fasting resulted in a significant decrease in serum iPTH (throughout the study period) as compared with the control period (P<0.05-0.001). No change was observed in sOC by fasting.

CONCLUSION

Food consumption has a small influence on the circadian variation in bone resorption, independent of PTH. The fall in iPTH during fasting may be secondary to an increased bone resorption produced by fasting.

Demonstration of the predominant urine osteocalcin fragments detectable by two-site immunoassays

We have isolated and characterized human osteocalcin (OC) fragments from pubertal urine. The fragments were isolated by immunoaffinity chromatography based on monoclonal antibody 6F9 and further purified by reverse phase chromatography. The major isolated forms, which were detectable with two-site immunofluorometric assays for serum OC, span residues 6-30 and 7-30 as determined by mass spectrometry and N-terminal amino acid sequencing. Full-length OC was not detectable in the supernatant fraction of urine but could be extracted with guanidinium hydrochloride from the sediment of urine samples. Urine samples from subjects with different menopausal status were measured by two different two-site assays. Urine OC (uOC) concentrations were 12- to 16-fold higher in the pubertal group than in the adult group. Also, the uOC concentration in a postmenopausal group was significantly higher than in a premenopausal group. The difference was 125% and 75% (values for p < 0.0001), respectively, when measured with the two assays. uOC concentrations in postmenopausal subjects on hormone replacement therapy were indistinguishable from the premenopausal subjects. The fact that uOC can be measured by a noncompetetive two-site assay design offers improved analytical sensitivity. Urine as the sample matrix is also especially interesting because the predominant markers of bone resorption, collagen type I peptides or cross-links, are performed on urine samples. Our results from the technical validation of two-site assays for uOC and from applying these to human pubertal and pre- and postmenopausal samples calls for more extensive clinical validation.

Dose response with fluticasone propionate on adrenocortical activity and recovery of basal and stimulated responses after stopping treatment

OBJECTIVE

To evaluate the dose-response relationship for adrenocortical activity with fluticasone propionate (FP) and to assess basal and dynamic markers after stopping treatment for 3 days.

PATIENTS AND DESIGN

Fourteen asthmatic patients were recruited: mean age 33.3 years, forced expiratory volume in 1 s (FEV1): 91.3% predicted, forced mid expiratory flow rate (FEF25-75): 58.1% predicted. A single blind study design was used comparing a placebo run-in with sequentially low, medium and high doses of FP and a placebo washout. All active treatments, placebo and washout were each for 3 days. FP was given at steady-state with twice daily divided dosing at 0800 h and 2200 h at doses of 375 micrograms, 875 micrograms, and 1750 micrograms per day.

MEASUREMENTS

A 100 micrograms i.v. bolus hCRF test was performed at 0800 h after the run-in and washout periods. Blood samples were taken for 0800 h serum cortisol and osteocalcin as well as an overnight 10 h urine collection for cortisol/creatinine excretion after the run-in period, each dose of active treatment and washout.

RESULTS

For serum cortisol (pre and post hCRF stimulation) there was no significant difference between placebo and washout values. Mean (SE) cortisol (nmol/1) values pre hCRF were run-in: 644.5 (59.7), washout: 550.3 (42.8) and post hCRF were run-in: 690.9 (42.9), washout: 719.1 (43.8). There was a significant (P < 0.05) difference between run-in vs medium and high doses for 0800 h serum cortisol, overnight urinary cortisol and overnight urinary cortisol/creatinine excretion; and vs high dose for serum osteocalcin. The fold difference (95% CI for difference) between run-in and high dose was: 2.2 (1.5-3.2) for overnight urinary cortisol, 2.5 (1.5-4.1) for overnight urinary cortisol/creatinine, 2.0 (1.1-3.6) for serum cortisol, and 1.2 (1.1-1.3) for serum osteocalcin.

CONCLUSION

Fluticasone propionate exhibited dose related adrenal suppression with treatment. The suppressive effects of fluticasone propionate on adrenocortical activity were greater than those observed on osteocalcin.

Dissociation of bone turnover in anorexia nervosa

Biochemical markers were measured to assess bone turnover in a cross-sectional study of 43 patients with anorexia nervosa; 28 were at their first assessment (untreated) with a body mass index (BMI) (median interquartile range) of 13.3 (2) kg/m2. A second group of 15 patients undergoing treatment (treated) had a median BMI of 17.6 (2.8) kg/m2. The median, interquartile range of urinary deoxypyridinoline (DPyd), a bone resorption marker, was raised in both groups compared with an age-matched control population [DPyd = 17.8 (15.2), 17.5 (16.4) and 9.2 (4.0) nmol/mmol creatinine, respectively]. Serum type 1 collagen carboxyterminal propeptide (P1CP), a marker of bone formation, was similar to controls in the untreated patients [112 (29) and 112 (78.5) ng/ml, respectively], but was significantly raised in the treated patients [163 (219) ng/ml, P < 0.05]. A second group of 21 patients was followed prospectively, on admission and during 8 weeks of intensive inpatient care (BMI on admission and after 8 weeks was 13.0 (2) and 16.7 (3) kg/m2, respectively). The resorption marker, serum type 1 collagen carboxyterminal telopeptide (1CTP) was raised on admission and remained high during treatment. P1CP and osteocalcin levels were similar to control levels on admission but increased with treatment, and after 8 weeks were 40% and 63% higher respectively than on admission. These findings suggest that in untreated anorexia nervosa there was uncoupling of bone turnover as bone resorption markers were raised without a concomitant increase in bone formation markers. As the condition was treated and patients gained weight, the formation markers also increased, leading to a more balanced, although higher, bone turnover.

Increased urinary crosslink levels in aseptic loosening of total hip arthroplasty

The diagnosis of aseptic loosening in total hip arthroplasty is predominantly based on clinical and radiographic evaluation. Loosening is usually associated with increased bone resorption at the interface. In this study we wanted to evaluate the diagnostic value of bone markers in aseptic loosening. We compared 50 patients with proven component loosening during surgery with 50 age-, sex-, and implant-matched patients without clinical or radiological signs of loosening. We measured serum markers of bone formation (bone-specific alkaline phosphatase, osteocalcin [OC], procollagen type I propeptides) and bone resorption (collagen n-telopeptide [NTX], deoxypyridinoline [DPYD], pyridinoline [PYD]). We found significantly increased levels of NTX, DPYD, PYD, and OC in the loosening group. The other markers showed no significant difference between both groups. We conclude that determination of urinary crosslinks may offer a new and valuable diagnostic method in the detection of aseptic loosening in total hip arthroplasty.

[Microalbuminuria as a risk factor for diabetic osteopathy in patients with IDDM and renal sufficiency]

Disturbances in bone marrow vascularisation can be one of the causes of diabetic osteopathy. The aim of the study was to answers the question if microalbuminuria as a results of capillary injury can be a sign of bone mineralisation disorders in IDDM renal sufficient patients. We examined 60 IDDM patients (30 women without menstruation disturbances; 30 men; age 25-36 years old). All the observed subjects were divided into groups: I-30 normoalbuminuric patients (0-29 mg/24 h); II-30 microabuminuric patients (30-295 mg/24 h). Bone mineral density (BMD) of femoral neck, lumbar spine (L2-L4) and total body was measured by dual energy X-ray absorptiometry (DEXA, Lunar). The biochemical parameters of bone turnover were measured both in serum and urine as follows: osteocalcine, total hydroxyproline (HPR, HPR/Cr), total alkaline phosphatase (AP) with bone fraction, total calcium (Ca, Ca/Cr) and inorganic phosphor (P). Microalbuminuric patients presented more severe bone turnover disturbances, shown by differences in: BMD and Z-score for femoral neck (p < 0.05), serum HPR (p < 0.05), AP (p < 0.05), AP (p < 0.01) and its bone fraction (p < 0.05). We proved the presence of statistically significant correlation coefficients for albuminuria and some densytometric and biochemical bone parameeters. Our results suggest that microalbuminuria can indirectly indicate the dynamic of bone turnover derangement in IDDM course. They are present mostly in the femoral neck, which because of the vascularisation type is particularly susceptible to subalimentation in the diabetic microangiopathy course.

Treatment of bone loss in oophorectomized women with a combination of ipriflavone and conjugated equine estrogen

OBJECTIVE

We previously reported that 0.625 mg/day of conjugated equine estrogen (CEE) could not prevent acute bone loss in the first year after oophorectomy. The effect of additional administration of ipriflavone on bone mineral density (BMD) and biochemical indices of bone remodeling were studied to investigate whether concurrent use of CEE and ipriflavone prevent acute bone loss in the early stages following surgical menopause.

METHODS

One-hundred and sixteen oophorectomized women were randomly divided into four groups according to treatment; group 1: placebo, n = 30; group 2: CEE (0.625 mg/day), n = 29; group 3: ipriflavone (600 mg/day), n = 30; group 4: CEE (0.625 mg/day) plus ipriflavone (600 mg/day), n = 27. Vertebral BMD was measured using dual energy X-ray absorptiometry (DEXA) and two biochemical indices of bone metabolism, urinary pyridinoline (Pyr) and serum intact human osteocalcin (hOC), were also measured before, 24 weeks, and 48 weeks after initiation of treatment.

RESULTS

BMD was reduced 48 weeks after treatment by 6.1, 3.9 and 5.1% in groups 1-3, respectively, but by only 1.2% in group 4. Pyr decreased by 49.5, 32.0 and 41.5% in groups 2-4, respectively. hOC also decreased by 45.2 and 21.6% in groups 2 and 4, but increased by 40.5% in group 3, suggesting an inhibitory action of CEE and ipriflavone on the turnover of bone metabolism and stimulatory action of ipriflavone on bone formation.

CONCLUSION

Concomitant use of ipriflavone with CEE from an early stage after oophorectomy inhibited bone loss and was considered to be effective in maintaining bone mass after oophorectomy.

[Gammopathies of indeterminant significance and osteoporosis: association or coincidence?]

OBJECTIVES

Osteoporosis is common in subjects over 70 years of age. Likewise, the incidence of monogammapathies of undetermined signification (MGUS) increases with age. We conducted this study to determine whether the biological and histomorphometric characteristics of osteoporosis in patients with MGUS are different from those in primary osteoporosis and to ascertain whether any cause and effect relationships could exist between MGUS and osteoporosis, excluding signs of active myeloma.

PATIENTS AND METHODS

Serum and urinary phosphorus and calcium, histomorphometric measurements, hormone levels and serum cytokines (IL1, IL6 and TNF alpha) were determined in 7 patients (mean age 71.8 years, 2 men and 5 women) with MGUS associated with osteoporosis with vertebral fractures (OP) and compared with those in 7 osteoporosis patients without MGUS matched for age, sex, and osteoporosis severity and 7 other age and sex matched patients with MGUS without OS. The MGUS + PS patients were followed for 9 years (4.5 to 20) so slowly progressive myeloma could be excluded.

RESULTS

Cytokine levels were the same in the three groups of patients but MGUS + OP patients had higher urinary calcium levels (ca/cr = 0.21 +/- 0.08 vs 0.12 +/- 0.1 (OP) and 0.13 (MGUS); p = 0.04), decreased osteocalcin levels (7 +/- 4.6 ng/ml vs. 12 +/- 4 (OP) and 11.5 +/- 5 (MGUS); p = 0.01) and increased surface resorption (8 +/- 1.4 vs. 3.6 +/- 1.2 (OP) and 5.5 +/- 1.7 (MGUS); p = 0.05).

DISCUSSION

It has been demonstrated that MGUS in patients with increased resorption and lower osteocalcin levels frequently progresses to active myeloma. The question is raised as to whether, in certain cases of MGUS, in situ stimulation of bone cells by monoclonal plasma cells could exist without ongoing transformation to active myeloma.