Bone Metabolism Status Research Articles

Bone-specific alkaline phosphatase activity in dairy cows

Bone-specific alkaline phosphatase is considered the single most accurate marker of bone formation. In this study, 75 healthy Holstein dairy cows in their first, second, third, fourth or fifth parities underwent serum bone-specific alkaline phosphatase quantification. The results indicate that enzyme activity values have a decreasing pattern with increasing order of parity (p 0.1). We concluded that bone-specific alkaline phosphatase measurement by heat inactivation provides a simple method to determine bone metabolic status and useful data to evaluate calcium availability in dairy cows.

Increased serum OPG in atrophic nonunion shaft fractures

BackgroundBone repair alteration is hypothesized for nonunion fracture pathogenesis. Since it is involved in osteoclast regulation, the RANK/RANKL/OPG system (receptor activator of nuclear factor kB/its ligand/osteoprotegerin) may play a role.Materials and methodsSerum OPG, free RANKL, bone alkaline phosphatase (BAP), osteocalcin (OC), and urinary deoxypyridinoline (DPD) were determined in 16 male patients (20–39 years) with long bone atrophic nonunion fractures. Serum markers were also measured in 18 age-matched male controls who healed from the same type of fractures within six months, and in 14 age-matched male controls who were healing from the same fractures one month after injury. One-way ANOVA and Bonferroni’s test were used for statistical analysis.ResultsOnly OPG was significantly higher (0.56 sd 0.11 ng/ml) in the patients compared to healed (0.26 sd 0.04 ng/ml; P < 0.001) and healing (0.29 sd 0.09 ng/ml; P < 0.001) controls. The patients’ DPD levels were normal. No correlations were found between bone markers and the characteristics of the subjects in all groups.ConclusionsA normal steady state of bone metabolism seems to be present in patients with atrophic nonunion fractures, despite the high serum OPG. The reason for the inability of the patients’ OPG to inhibit osteoclastic activity is unknown. Osteoblast activity also appears normal, so another cellular source of OPG can be hypothesized.

Intérêt de l’imagerie scintigraphique, à Madagascar, dans le diagnostic de l’adénome parathyroïdien ectopique – à propos d’un cas

This study reports the first case of ectopic parathyroid adenoma, diagnosed in the Department of Nuclear Medicine in Antananarivo. This clinical vignette illustrates the interest of the MIBI-Tc-99 m scan in locating this adenoma and its diagnostic confirmation after six years of erratic diagnosis. A whole body bone scintigraphy has also allowed to assess the state of bone metabolism and study outbreaks of fracture. The parathyroid scintigraphy was carried out after intra-venous administration of 666 MBq of MIBI-Tc99m. Dynamic images, static early and late static were acquired with a gamma camera E-Cam Siemens. The whole body bone scan was carried out after administration of 555 MBq of MDP-Tc-99 m. The results evidenced the presence of an para-aortic increased uptake area pointing to a left parathyroid adenoma. The persistence of a late left submaxillary increased uptake area raises, however, a reservation about the existence of a second adenoma. The bone scan displayed global skeletal remodeling, non suggestive of metastases, as it was mentioned with the CT-scan. In a diagnostic tools limited environment, skeletal pain refractory to painkillers, a chronic hypercalcemia associated with an increased parathyroid hormone level, should trigger the scintigarphic exploration in order to avoid bone and renal complications.

Serum Levels of TRAP5b, a New Bone Resorption Marker Unaffected by Renal Dysfunction, as a Useful Marker of Cortical Bone Loss in Hemodialysis Patients

Tartrate-resistant acid phosphatase (TRAP) 5b is a new marker of bone resorption that is unaffected by renal dysfunction. The significance of TRAP5b was assessed in hemodialysis (HD) patients. Serum concentrations of TRAP5b and cross-linked N-telopeptide of type I collagen (NTX) were determined as bone resorption markers, and those of bone alkaline phosphatase (BAP) and intact osteocalcin (OC) were measured as bone formation markers in 58 HD patients. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry twice in the distal third of the radius, with a 2-year interval between measurements. Serum TRAP5b correlated significantly with BAP, intact OC, intact parathyroid hormone (PTH), and especially serum NTX. TRAP5b, NTX, BAP, and intact OC all correlated significantly with BMD at the time of the second measurement; and TRAP5b, NTX, and intact OC, but not BAP and intact PTH, correlated significantly with the annual change in BMD during the 2-year period. Among the bone markers, patients in the highest tertile for serum TRAP5b and intact OC showed the fastest rate of cortical bone loss. The sensitivity and specificity for detection of rapid bone loss were 57.9% and 76.9%, respectively, for serum TRAP5b. Measurement of serum TRAP5b, as well as intact OC, may be a clinically relevant assay for estimation of bone metabolic status in HD patients, although serum intact OC accumulates in uremic serum.

Running has a negative effect on bone metabolism and proinflammatory status in male aged rats

Animal models for male osteoporosis are scarce. This study aimed at identifying the impact of different living conditions on bone structure and metabolism as well as the inflammatory status in a rat model of age-related male osteoporosis. Bone mineral density, bone histomorphometric data, ex vivo osteoclast generation, and bone metabolism serum marker as well as intracellular cytokine expressions were evaluated in 23-month-old male Sprague–Dawley rats subjected to different housing conditions from the age of 5 months. Running rats were housed individually and were exercised voluntarily in running wheels attached to their cages. Dieting rats were housed individually, too, but were fed to pair weight with the running rats. Walking rats were exercised mildly by use of a treadmill (800 m/day, 5 days a week) and social rats were kept as four in a cage and fed ad libitum. Whereas no marked differences could be found for bone mineral density, trabecular bone volume as well as trabecular bone surface were diminished in walking rats. The ex vivo osteoclast generation assay revealed no significant differences between groups. Osteoblasts of running rats were not only decreased in number, but displayed also a lower activity as indicated by decreased serum osteocalcin levels. Osteoclast activity was increased in the same group as indicated by elevated CTX (c-terminal telopeptide of type I collagen) levels. Additionally, production of tumor necrosis factor (TNF)-α and interferone (IFN)-γ by CD8 + T cells was elevated in running rats. In conclusion, running has a negative effect on bone metabolism and proinflammatory status in male aged rats.

Long-term consumption of isoflavone-enriched foods does not affect bone mineral density, bone metabolism, or hormonal status in early postmenopausal women: a randomized, double-blind, placebo controlled study

Background: Osteoporosis is a major health problem. It was hypothesized that isoflavone-containing products may be a potential alternative to hormone replacement therapy for preventing bone loss during the menopausal transition.Objective: The objective was to investigate whether the consumption of isoflavone-enriched foods for 1 y affects bone mineral density, bone metabolism, and hormonal status in early postmenopausal women.Design: This was a randomized, double-blind, placebo-controlled, parallel, multicenter trial. Two hundred thirty-seven healthy early postmenopausal women [mean (±SD) age of 53 ± 3 y and time since last menses of 33 ± 15 mo] consumed isoflavone-enriched foods providing a mean daily intake of 110 mg isoflavone aglycones or control products for 1 y while continuing their habitual diet and lifestyle. Outcome measures included bone mineral density of the lumbar spine and total body, markers of bone formation and bone resorption, hormones, isoflavones in plasma and urine, safety variables, and adverse events.Results: Consumption of isoflavone-enriched products did not alter bone mineral density of the lumbar spine and total body or markers of bone formation and bone resorption. Hormone concentrations did not differ between the isoflavone and control groups. Consumption of isoflavone-enriched products resulted in increased isoflavone concentrations in plasma and urine, whereas control products did not. This finding indicated good compliance with treatment. Subgroup analysis did not support an effect of equol phenotype on bone density. The intervention had no effect on a range of safety variables and reported adverse events.Conclusion: Consumption of foods containing 110 mg/d of soy isoflavone aglycone equivalents for 1 y did not prevent postmenopausal bone loss and did not affect bone turnover in apparently healthy early postmenopausal white women. This trial was registered at clinicaltrials.gov as NCT00301353.

Elevation of Intact Parathyroid Hormone Level Is a Risk Factor for Low Bone Mineral Density in Pretransplant Patients With Liver Diseases

The purpose of this study was to investigate the frequency and risk factors for low bone mineral density (BMD) among patients awaiting liver transplantation. BMD of the lumbar spine (LS) and femoral neck (FN), measured by dual-energy X-ray absorptiometery (DEXA), were obtained in 64 pretransplant patients. We measured markers of bone metabolism including serum calcium, phosphorus, serum 25-hydroxyvitamin D (25-OH D), intact parathyroid hormone (iPTH), bone alkaline phosphatase (BAP), osteocalcin (OC), and urinary deoxypyridinoline/creatinine (DPD/Cr) ratio. Osteoporosis and osteopenia (low BMD) were observed in 36 patients (36/64, 56.2%), including 6 cases of osteoporosis (6/64, 9.3%) and 30 cases of osteopenia (30/64, 46.9%). Of all variables, cholestatic liver disease and elevated levels of iPTH were significantly associated with low BMD. Moreover, elevated iPTH level was identified as an independent risk factor for low BMD ( P < .05, OR = 1.017, 95% CI = 1.001–1.032) by multivariate analysis. The median level of iPTH was increased to 55.6 pg/mL (range, 7.8–337 pg/mL) in the low BMD group, while the median level was 33 pg/mL (range, 3–162 pg/mL) in the normal BMD group ( P < .05). This study revealed a high incidence of low BMD in the pretransplant patients with liver diseases. The elevated iPTH level was the predominant risk factor for low BMD. We suggest that both BMD and iPTH examinations be considered routine tests to identify the status of bone mass and bone metabolism among recipients prior to liver transplantation.

Alveolar bone loss in liver transplantation patients: relationship with prolonged steroid treatment and parathyroid hormone levels

To evaluate the relationship among alveolar bone loss (ABL), bone status and calcium-regulating hormones in liver transplantees. Twenty-one liver transplantees underwent a full oral examination. The correlations among bone densitometry, bone metabolic status and drug treatment were examined. Twelve patients had osteopenia, and six were osteoporotic. ABL was 4.33+/-2.32 mm (range 0.67-9.92). Parathyroid hormone (PTH) levels ranged from 14 to 106 (mean 55.2+/-26.4). The mean 25(OH)D(3) was 11.68+/-4.7, range 3.5-21.1 ng/ml. Nine patients were vitamin D deficient (<10 ng/ml); none of the patients had 25(OH)D(3) levels > or =30 ng/ml. No correlation was found between ABL and current or total glucocorticoids dose, although there was an inverse relation with the duration of treatment (r =-0.474, p=0.03). A positive correlation was found between ABL, PTH (r =0.419, p=0.059) and hip bone mineral density (BMD) (r=0.482, p=0.027). ABL correlated closely with age, PTH, glucocorticoid treatment (duration) and hip BMD (r =0.810, p=0.004). The majority of liver transplant patients had insufficient 25(OH)D(3) serum levels. Changes in calcium-regulating hormones and hip BMD were correlated with ABL. Therefore, therapeutic intervention aimed at treating vitamin D deficiency and secondary hyperparathyroidism should be considered in these patients. The benefits of vitamin D treatment in the management of secondary hyperparathyroidism and possible decrease in ABL deserve further evaluation in controlled trials.

Pakistani immigrant children and adults in Denmark have severely low vitamin D status

To determine vitamin D and bone status in adolescent girls, pre-menopausal women and men of Pakistani origin, to single out determinants of vitamin D status and to determine the association between vitamin D status, bone metabolism and bone status. Cross-sectional study, Copenhagen (55 degrees N), January-November. Serum 25-hydroxyvitamin D (S-25OHD), serum intact parathyroid hormone (S-iPTH), bone turnover markers and whole body and lumbar spine bone mineral density were measured. Sun, smoking and clothing habits, age, body mass index (BMI), and vitamin D and calcium from food and from supplements were recorded. Thirty-seven girls (median age, range: 12.2 years, 10.1-14.7), 115 women (36.2 years, 18.1-52.7) and 95 men (38.3 years, 17.9-63.5) of Pakistani origin (immigrants or descendants with Pakistani parents) took part in the study. Median concentration of S-25OHD was 10.9, 12.0 and 20.7 nmol/l for girls, women and men, respectively. Forty-seven per cent of the girls, 37% of the women and 24% of the men had elevated S-iPTH, and there was a negative relationship between S-iPTH and S-25OHD. Use of vitamin D-containing supplements had a positive association with S-25OHD for men (P=0.04) and women (P=0.0008). Twenty-one per cent of the women and 34% of the men had osteopenia. Neither S-25OHD nor S-iPTH was associated with lumbar spine or whole body bone mineral content. Severely low vitamin D status and elevated S-iPTH is common among Pakistani immigrants in Denmark. The low vitamin D status is not associated with bone markers or bone mass among relatively young Pakistanis.

Parathyroid hormone and large related C-terminal fragments increase at different rates with worsening of renal function in chronic kidney disease patients. A possible indicator of bone turnover status?

The intact parathyroid hormone (PTH) serum value has been the non-invasive biomarker of choice for the early diagnosis of renal bone disease in the chronic kidney disease (CKD) patient population. It has now been known that the intact PTH assay value is the sum of 1-84 PTH (true hypercalcemic PTH) and large C-terminal PTH fragments, mainly 7-84 PTH, a fragment with hypocalcemic hormone actions. The aim of this study was to investigate the differences among the different functional stages of CKD in the following PTH parameters: intact PTH, 1-84 PTH, 7-84 PTH, and the ratio 1-84 PTH/7-84 PTH. GFR (clearance of 99mTc-DTPA) was measured in 164 (85 males and 79 females) adult CKD patients with different degrees of renal function impairment (serum creatinine 0.50 12.1 mg/dl, mean 2.00). Plasma concentrations of calcium, phosphate, 1-84 PTH and intact PTH were also measured. The value of 7-84 PTH was calculated as the difference between intact PTH and 1-84 PTH. The reduction of, GFR was accompanied by an increase of intact PTH, with a prevalent increase of 7-84 PTH over 1-84 PTH, resulting in a decrease of the ratio 1-84 PTH/7-84 PTH. The values of 7-84 PTH showed a discrimination between Stages 1 and 2 (GFR > 60 ml/min ) and Stage 3 (GFR 30 60 ml/ min) CKD patient populations. In fact, 7-84 PTH was already significantly increased in patients at CKD Stage 3. The analysis of individual patients indicated that a low value (< 1.4) of the ratio 1-84 PTH/7-84 PTH, suggestive for low bone turnover, was already found in more than 20% of CKD Stage 3 patients. The results of the present study demonstrate that the reduction in GFR is accompanied by a higher increase in 7-84 PTH with respect to 1-84 PTH, which suggests the possibility that bone metabolism and calcemic status are already reduced in patients with moderate renal failure (CKD Stage 3).

Effects of estrogen-progestin therapy on serum levels of RANKL, osteoprotegerin, osteocalcin, leptin, and ghrelin in postmenopausal women

The aim of this study was to evaluate the effects of estrogen-progestin therapy on serum levels of receptor-activating nuclear factor kappabeta ligand (RANKL), osteoprotegerin, osteocalcin, leptin, and ghrelin in a cross-sectional study of 99 healthy postmenopausal women conducted at the Menopause Clinic of our department. In this cross-sectional, observational study, 99 participants were divided into two groups. Group A was composed of 77 postmenopausal women who had never received estrogen-progestin therapy, and group B was composed of 22 postmenopausal women who had received transdermal 17beta-estradiol at a dose of 50 microg/day in a continuous regimen for at least 24 months and nomegestrol at a dose of 5 mg/day for 12 days/month in a sequential regimen. All participants underwent blood sampling in the morning and quantitative ultrasound bone-densitometry measurement of the proximal phalanges of the dominant hand. T score and amplitude-dependent speed of sound were significantly higher in group B than in group A. No significant differences in RANKL, osteoprotegerin, and osteocalcin were observed between the two groups. Serum leptin levels were significantly lower in group B than in group A, whereas ghrelin was significantly higher in group B than in group A. The data gathered in this preliminary study indicate that estrogen-progestin therapy may protect against postmenopausal bone loss, but this protective effect does not seem to be exerted through action on the RANK-RANKL-osteoprotegerin system. Similarly, although several reports suggest that leptin and ghrelin are involved in bone metabolism, we could not detect any important correlation of these two hormones with bone metabolism or bone status in treated and untreated postmenopausal women. Because of the limited number of treated participants and the study design, the results of this preliminary study must be confirmed in larger, prospective, longitudinal studies.

Bone mineral density and bone turnover markers of patients with Behçet's disease

Behçet's disease (BD) is a systemic inflammatory disease of unknown aetiology. The pathogenesis of rheumatological findings and the status of bone metabolism in this disease are unknown. Inflammatory diseases may predispose to a decrease in bone mineral density (BMD) and there are many studies concerning osteoporosis in chronic inflammatory diseases. The aim of this study was to investigate BMD and bone turnover markers in patients with BD. Thirty BD patients (17 male and 13 female patients, mean age 36.9+/-12.6 years) and a total of 30 age- and sex-matched healthy controls (17 male and 13 female controls, mean age 34.9+/-8.95 years) recruited from the general population were enrolled in the study. Bone mineral density was measured at the lumbar spine (L1-4) and the left hip (total hip) using dual energy X-ray absorptiometry. Serum samples were collected between 8 and 10 am after overnight fasting. Serum calcium (Ca), phosphate (P), parathormone (PTH), total alkaline phosphatase (ALP), osteocalcin (OC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were measured. Free deoxypyridinoline cross-links (DPD) in second-void urine and total daily urinary calcium excretion were analysed. No statistically significant difference in lumbar spine or femoral BMD and bone turnover markers were found between BD patients and control groups (P>0.05). Although it is difficult to draw definite conclusions because of the limited number of patients involved, our study indicates that bone mineral density and bone turnover markers in Behçet's disease were no different than in healthy subjects.

Bone Density in Elite Judoists and Effects of Weight Cycling on Bone Metabolic Balance

Weight cycling has been shown to exert negative effects on bone metabolism and bone mass, whereas weight-bearing activity is positively associated with bone mineral density (BMD). Bone health in judoists and effects of weight cycling on bone metabolism have not previously been investigated. To examine potential disrupter and stimulators of bone integrity, this study analyzed bone parameters at baseline and the effects of the first weight cycle of the season on bone metabolic status in 48 male and female elite judoists. Body composition and lumbar, femoral, and total body BMD were evaluated by dual-energy x-ray absorptiometry. Cortisol, osteocalcin, C-terminal telopeptide of type I collagen (CTx), and bone uncoupling index (UI) were measured in judoists at normal body weight, after weight reduction, and after regaining weight. As a comparison, a control group of moderately active students was included at baseline. Training, menstrual status, and calcium intake were assessed by questionnaires. EUweighted judoists displayed high BMD and an increased rate of bone formation. Precompetitive weight loss averaged 4 +/- 0.3% of body weight and induced an acute rise in cortisol (81%, P < 0.05) and CTx (33%, P < 0.0001), with a metabolic imbalance in favor of bone resorption. A 4 +/- 0.5% weight regain restored a positive UI in favor of bone formation. Metabolic responses were not dependent on gender. BMD was unaltered by weight cycling. Increased bone formation rate pertaining to judo athletes lent protection from alterations in bone metabolic balance associated with weight cycling. This observation suggests that powerful osteogenic stimuli provided by judo's unique biomechanical environment may help prevent bone loss associated with weight loss.

Follow-up of patients with celiac disease: Achieving compliance with treatment

Celiac disease is the only autoimmune condition for which we know the environmental trigger: gluten. Complete removal of gluten from the diet in a patient with celiac disease should result in symptomatic, serologic, and histologic remission. However, compliance with the gluten-free diet, especially in the United States, is extremely challenging. Compliance can be measured both noninvasively, by dietary history and measurement of serum antibodies, and invasively, by using endoscopic and histologic criteria. The advantages and disadvantages of these various modalities are discussed. The highest rates of compliance are reported in patients who are diagnosed as young children, whereas adolescents and those diagnosed via mass serologic screening have the most transgressions. Barriers to compliance include the poor palatability of gluten-free foods, confusing food-labeling practices, and common comorbid psychologic burdens such as anxiety and depression. Because celiac disease is a multisystemic disorder, physicians need to be aware of the potential autoimmune, nutritional, and malignant complications. An algorithm for the follow-up and management of the newly diagnosed celiac disease patient is presented, which includes regular follow-up; measurement of serum antibodies; eliciting a detailed dietary history; and examination for signs and symptoms of nutritional deficiencies, malignancy, and other autoimmune diseases. Ideally, a team approach to the follow-up of the newly diagnosed patient should include regular supervision by an interested physician, medical nutritional counseling by a registered dietician, and access to local and national support groups knowledgeable about this condition.

Changed bone status in human immunodeficiency virus type 1 (HIV‐1) perinatally infected children is related to low serum free IGF‐I

Adults and children affected by human immunodeficiency virus type-1 (HIV-1) infection show bone demineralization. Little is known about skeletal status using a quantitative high-frequency ultrasound (QUS) technique in these patients. To evaluate the bone quality and assess the role of the IGF system in the bone metabolism and skeletal status of HIV-1 perinatally infected children. Serum free and total IGF-I, IGFBP-3, serum osteocalcin level, urinary deoxypyridinoline concentration, spontaneous interleukin-6 (IL-6) release and broadband ultrasound attenuation (BUA) were evaluated in 44 prepubertal children who had perinatal HIV-1 infection. The patients were divided into two groups depending on the severity of their clinical condition: group 1 (23 children with no or mild clinical symptoms, mean age 8.0 +/- 2.9 years) and group 2 (21 children with severe clinical symptoms, mean age 8.58 +/- 2.47 years). Fifty-five healthy age- and sex-matched controls were analysed for comparison. Compared with group 1 and the controls, group 2 patients showed a significantly reduced BUA Z-score (P < 0.001), and significantly reduced concentrations of serum osteocalcin (P < 0.001) and urinary deoxypyridinoline (P < 0.001 and P < 0.05, respectively). Group 2 patients also showed significantly reduced serum free IGF-I (P < 0.001) and total IGF-I (P < 0.05) levels compared with the controls, but not with group 1. No statistically significant differences were found between the three groups with regard to IGFBP-3. Group 2 patients showed significantly higher spontaneous IL-6 release than group 1 patients and controls (P < 0.001). BUA Z-scores displayed a significant correlation with free IGF-I in group 2 (r = 0.96; P < 0.001), group 1 (r = 0.56; P = 0.005) and controls (r = 0.50; P < 0.001). Our study shows that only patients affected by perinatal HIV-1 infection with severe clinical manifestations present significant changes in bone quality and bone metabolism. Our data also show that impairment of skeletal status is related to reduction in serum total and free IGF-I. Children with perinatal HIV-1 infection, because of a considerable improvement in life expectancy, seem at great risk of not obtaining an optimal bone mass. A possible therapeutic approach should be considered in these children.

Bone assessment of female long-distance runners.

The objective of the present study was to investigate the effects of long-distance training on the bones in different growth stages by evaluating the bones of female high school athletes and female adult athletes who engage in long-distance training. Thirteen female high school athletes (aged 15-17 years) and 7 female adult athletes (aged 21-25 years) were enrolled in the present study. Bone mineral density (BMD) and bone mineral content (BMC) were measured using dual X-ray absorptiometry (DXA). Cortical bone status was also evaluated by measuring the tibial speed of sound (t-SOS). The bone metabolic status was evaluated by osteocalcin (OC) and tartrate-resistant acid phosphatase (TRAP). OC ( P < 0.01) and lumbar BMD ( P < 0.05) were significantly higher in high school athletes who were in the modeling period than in the adult athletes. Leg BMD ( P < 0.01) and t-SOS ( P < 0.05) were significantly higher in adult athletes who were in the remodeling period than in high school athletes. When lumbar BMD and leg BMD were compared according to menstrual conditions, the high school athletes with regular menstruation showed a significantly higher level of bone density than those having irregular or absent menstruation. These results indicate that the effect of long-distance training on bone metabolism is influenced strongly by sex hormones during late puberty. We concluded that the effect of long-distance training on bone metabolism in the female high school athletes (i.e., during puberty) was different from that in the adult athletes.

Authors’ Response: Cortical Bone Density Is Normal in Prepubertal Children with Growth Hormone (GH) Deficiency, but Initially Decreases during GH Replacement due to Early Bone Remodeling

Dual energy x-ray absorptiometry (DEXA) has revealed that GH- deficient adults gain in bone mineral density during GH therapy. Measurements of volumetric bone density (grams per cubic centimeter vs. grams per square centimeter) and structure, however, are achieved through peripheral quantitative computed tomography (pQCT). In 45 prepubertal GH-deficient children, we studied pQCT measurements before the start and for 12 months of GH treatment. Serum alkaline phosphatase (AP), procollagen I carboxyl-terminal propeptide (PICP), and deoxypyridinoline reflected bone metabolism status. Findings at the start of GH treatment were (mean sd score): bone area, −0.44; cortical density, −0.03; cortical area, −1.32; cortical thickness, −1.41; and marrow area, +0.66. At 12 months, cortical density had fallen to −0.73 (P < 0.001), whereas cortical area and thickness, and marrow area did not change. AP, PICP, and deoxypyridinoline increased significantly within the first 3 months (increase: AP, 66.5 U/liter; PICP, 72 μg/l...

Competitive season of triathlon does not alter bone metabolism and bone mineral status in male triathletes.

This longitudinal study evaluated the effects of a triathlon season on bone metabolism and hormonal status. Seven male competitive triathletes (mean age 19.3 years, range 18 - 20) with 5.0 +/- 0.3 years of competition experience were tested twice during the season: at the beginning of training and 32 weeks later. Total and regional bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry, while bone turnover was evaluated by specific biochemical markers: bone-specific alkaline phosphatase (B-ALP), osteocalcin, and urinary type I collagen C-telopeptide. In addition, sexual, calciotropic and somatotropic hormones were also analyzed. After 32 weeks, a BMD increase was found at the lumbar spine (1.9 %; p = 0.031) and skull (3.1 %; p = 0.048), while no variation was observed for total body or at the proximal femur. The B-ALP level decreased (-23.2 %; p = 0.031), but no variation was found for the other bone markers. 1.25 (OH) (2)D3, IGF-1 and the bioavailability IGF-1 index (IGF-1/IGFBP-3) increased by 18.3 % (p = 0.047), 29 % (p = 0.048), 33 % (p = 0.011), respectively, while PTH, testosterone, IGFBP-3 and cortisol concentrations were unchanged. In conclusion, the triathlon season had a moderately favourable effect on BMD, although a slowing down of bone formation activity was observed. No variation in hormonal levels was observed that could have limited the effects of exercise on bone tissue.

Effects of red algae cultivated with deep-sea water on the oxidation–reduction status of liver, lung, brain, and bone metabolism in SAMP1 and SAMR1

We investigated the potential of red algae cultivated with deep-sea water (D) as dietary anti-oxidants to ameliorate the redox levels in the main organs and in bone metabolism using SAMP1 and its control SAMR1, in comparison with the same algae cultivated with surface seawater. Only the D group showed marked increases of glutathione (GSH) levels in the liver (R1, 134%) and brain (R1, 128% and P1, 126%) as well as activities of GSH non-dependent peroxidase in the liver (R1, 138%) and the brain (R1, 117% and P1, 112%) but not GSH-dependent peroxidase. The D diet also exhibited beneficial effects on bone metabolism; elevations of femoral calcium, phosphorus, hydroxyproline for collagen, hexosamine for polysaccharides, and suppression of urinary excretion of hydroxyproline as an index of increased bone resorption. A three-point bending test showed that the D diet increased the stiffness and the strength of the femur, which correlated with increases in femoral calcium and phosphorus contents. The results suggest that red algae of the Gracilaria sp. cultivated with deep-sea water has the potential to ameliorate degenerative diseases of aging.

Do markers of bone metabolism reflect the presence of a high- or low-turnover state of bone metabolism?

A pathophysiological concept of osteoporosis therapy - antiresorptive treatment of high-turnover osteoporosis (e. g. bisphosphonates, raloxifen) and osteoanabolic treatment of low-turnover osteoporosis (e. g. parathyroid hormone) - is clinically and economically reasonable to enable physicians to decide who will benefit most from which drug. Biochemical bone markers in serum and urine are frequently used for the diagnosis of high- or low-turnover osteoporosis. We investigated whether bone marker levels reflect the histologically diagnosed high- or low-turnover state of osteoporosis. 175 bone biopsies of male and female osteoporotic patients (WHO criteria) were histologically classified in high- and low-turnover osteoporosis and associated with bone marker levels in serum and urine. Patients with any osteotropic therapy and with fractures were excluded. There were no significant differences between patients with high- and low-turnover osteoporosis with regards to osteocalcin, DPD crosslinks, alkaline phosphatase, 25-OH vitamin D(3), parathyroid hormone and bone mass (spine and hip). Single measurements of biochemical bone markers in serum and urine do not allow a valid differentiation between histologically diagnosed high- and low-turnover states of osteoporosis. The therapeutic concept of treating with osteoanabolic drugs requires valid diagnostic criteria for the differentiation between high- and low-turnover state of bone metabolism which can be provided by a bone biopsy but not by single measurements of bone markers.