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Bone Turnover Rate (bone + turnover_rate)
Selected AbstractsOsteoprotegerin and bone turnover markers in heavily pretreated HIV-infected patientsHIV MEDICINE, Issue 3 2005E Seminari Objectives To characterize osteoprotegerin (OPG) levels, bone remodelling and bone mineral density (BMD) in heavily pretreated HIV-infected patients on antiretroviral therapy, and to evaluate the clinical factors associated with bone density decline. Methods Heavily pretreated (>5 years) HIV-positive patients were enrolled in this cross-sectional, observational study, which was based on a total body bone densitometry examination and a comprehensive evaluation of bone and mineral parameters. Results Sixty-eight patients (55 male and 13 female) with a median age of 41 years (range 25,60 years) were included in the study. Their antiretroviral treatment lasted for 82 months. On the basis of the World Health Organization criteria, nine patients (13.2%) were osteoporotic [T-score<,2.5 standard deviation (SD)] and 19 patients (27.9%) were osteopenic (T-score between,1 and,2.5). The principal outcomes associated with the presence of a low BMD were high OPG and lysylpyridinoline/creatinine ratio (Dpd) values. Most of the patients (39 of 48; 81.25%) showed vitamin D insufficiency [Vitamin D (25(OH)D)<18 ng/mL] with secondary hyperparathyroidism (13 of 50 patients: 26%), which proved to be correlated to osteocalcin (BGP) levels [parathyroid hormone (PTH) vs. BGP: r=0.34; P<0.01]. There was an inverse correlation between T-scores and serum osteocalcin and alkaline phosphatase (AP) levels, on one hand, and Dpd, on the other. High AP and Dpd values were associated with relative risks of 4.1 [95% confidence interval (CI)=1.01,17.6] and 7.2 (95% CI=1.67,31.03), respectively, of a pathological T-score. Multivariate analysis revealed that the factors associated with the presence of osteopenia or osteoporosis were older age and lower body mass index. Conclusions About 40% of our heavily pretreated subjects with advanced HIV infection had a low BMD, and 56% (24 of 44 patients) showed a high bone turnover rate with marked osteoclast activation. High OPG levels may protect against bone resorption. [source] Type I Collagen Racemization and Isomerization and the Risk of Fracture in Postmenopausal Women: The OFELY Prospective StudyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2002Patrick Garnero Ph.D. Abstract The Asp1211 residue of the1209AHDGGR1214 sequence of the C-terminal cross-linking telopeptide of type I collagen (CTX) can undergo spontaneous post-translational modifications, namely, racemization and isomerization, which result in the formation of four isomers: the native form (,- L) and three age-related forms, that is, an isomerized form (,- L), a racemized form (,- D), and an isomerized/racemized (,- D) form. Previous studies have suggested that changes in the pattern of type I collagen racemization/isomerization, which can be assessed in vivo by measuring the degradation products of the CTX isoforms, may be associated with alterations of bone structure. The aim of this study was to examine prospectively the value of the different urinary CTX isoforms and their related ratio in the prediction of osteoporotic fractures in 408 healthy untreated postmenopausal women aged 50-89 years (mean, 64 years) who were part of the OFELY cohort. During a median 6.8 years follow-up, 16 incident vertebral fractures and 55 peripheral fractures were recorded in 65 women. The baseline levels of the four CTX isoforms in women who subsequently had a fracture were compared with those of the 343 women who did not fracture. At baseline, women with fractures had increased levels of ratios of native ,- L -CTX to age-related isoforms (,- L, ,- D, and ,- D) compared with controls (p < 0.01). In logistic regression analysis after adjustment for age, prevalent fractures, and physical activity, women with levels of ,- L/,- L, ,- L/,- D, and ,- L/,- D -CTX ratios in the highest quartile had a 1.5- to 2-fold increased risk of fractures compared with women with levels in the three lowest quartiles with relative risk (RR) and 95% CI of 2.0 (1.2-3.5), 1.8 (1.02-2.7), and 1.5 (0.9-2.7), respectively. Adjustment of ,- L/,- L and ,- L/,- D -CTX ratios by the level of bone turnover assessed by serum bone alkaline phosphatase (ALP)- or femoral neck bone mineral density (BMD) decreased slightly the RR, which remained significant for the ,- L/,- L -CTX ratio (RR [95%] CI, 1.8 [1.1-3.2] after adjustment for bone ALP, 1.8 [1.03-3.1] after adjustment for BMD, and 1.7 [0.95-2.9] after adjustment for both bone ALP and BMD). Women with both high ,- L/,- L -CTX ratio and high bone ALP had a 50% higher risk of fracture than women with either one of these two risk factors. Similarly, women with both increased CTX ratio and low femoral neck BMD (T score < ,2.5) had a higher risk of fracture with an RR (95% CI) of 4.5 (2.0-10.1). In conclusion, increased urinary ratio between native and age-related forms of CTX, reflecting decreased degree of type I collagen racemization/isomerization, is associated with increased fracture risk independently of BMD and partly of bone turnover rate. This suggests that alterations of type I collagen isomerization/racemization that can be detected by changes in urinary CTX ratios may be associated with increased skeletal fragility. [source] Influence of sex hormones on the periodontiumJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2003Paulo Mascarenhas Abstract Objectives: Sex hormones have long been considered to play an influential role on periodontal tissues, bone turnover rate, wound healing and periodontal disease progression. The objectives of this review article are to (1) address the link between sex hormones and the periodontium, (2) analyse how these hormones influence the periodontium at different life times and (3) discuss the effects of hormone supplements/replacement on the periodontium. Materials and Methods: Two autonomous searches were performed in English language utilizing Medline, Premedline and Pubmed as the online databases. Publications up to 2002 were selected and further reviewed. In addition, a manual search was also performed including specific related journals and books. Results: It is certain that sexual hormones play a key role in periodontal disease progression and wound healing. More specifically, these effects seem to differentiate by gender as well as lifetime period. In addition, the influence of sex hormones can be minimized with good plaque control and with hormone replacement. Conclusion: Despite profound research linking periodontal condition with sex hormones kinetics, more definitive molecular mechanisms and therapy still remain to be determined. Zusammenfassung Männliche und weibliche Sexualhormone wurden schon lange einen wichtigen Einfluss auf das parodontale Gewebe, die Knochenumsatzrate, die Wundheilung und die parodontale Erkrankungsprogression ausübend betrachtet. Der Einfluss dieser Hormone auf das Parodontium unterscheidet sich zu verschiedenen physiologischen Phasen (z.B. Pubertät, Schwangerschaft, post Menopause) und mit der Einnahme von Pharmaka (z.B. Antikonzeptiva, Hormonsubstitution). Deshalb ist der Zweck dieses Reviewartikels (1) die Beziehung zwischen Sexualhormonen und dem Parodontium zu beschreiben, (2) die Analyse des Einflusses dieser Hormone auf das Parodontium zu unterschiedlichen Lebenszeiten und (3) die Effekte von Hormonunterstützung/substitution auf das Parodontium zu diskutieren. Résumé On a longtemps considéré que les hormones sexuelles, aussi bien masculines que féminines, jouaient un rôle important sur les tissus parodontaux, le taux de remaniement osseux, la cicatrisation et la progression de la maladie parodontale. L'influence de ces hormones sur le parodonte est différente en fonction des divers conditions physiologiques (par exemple, la puberté, la grossesse, et après la ménopause) et les prises de médicaments (par exemple, la pillule contraceptive et les traitements hormonaux de substitution). Aussi, cette revue critique de la littérature se propose (1) de faire le point sur les liens entre les hormones sexuelles et le parodonte (2) d' analyser la façon dont ces hormones influencent le parodonte lors des différentes étapes de la vie, et (3) discuter les effets des hormones de substitution sur le parodonte. [source] Recovery of Trabecular and Cortical Bone Turnover After Discontinuation of Risedronate and Alendronate Therapy in Ovariectomized RatsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2008Robyn K Fuchs Abstract Alendronate (ALN) and risedronate (RIS) are bisphosphonates effective in reducing bone loss and fractures associated with postmenopausal osteoporosis. However, it is uncertain how long it takes bone turnover to be re-established after treatment withdrawal, and whether this differs between the two drugs. The objective of this study was to determine the time required to re-establish normal bone turnover after the discontinuation of ALN and RIS treatment in an animal model of estrogen-deficiency osteoporosis. Two hundred ten, 6-mo-old female Sprague-Dawley rats were ovariectomized and 6 wk later were randomized into baseline controls (n = 10) and four treatment groups (n = 50/group): vehicle-treated controls (CON; 0.3 ml sterile water), ALN (2.4 ,g/kg), low-dose RIS (RIS low; 1.2 ,g/kg), and high-dose RIS (RIS high; 2.4 ,g/kg). Treatments were administered 3 times/wk by subcutaneous injection. Baseline controls were killed at the initiation of treatment. Other groups were treated for 8 wk, and subgroups (n = 10/ treatment group) were killed 0, 4, 8, 12, and 16 wk after treatment was withdrawn. Static and dynamic histological analyses were performed for cortical (tibial diaphysis) and trabecular (proximal tibia and L4 vertebrae) bone. DXA and mechanical testing was performed on the L5 vertebra. After 8 wk of treatment, trabecular bone turnover rates were significantly suppressed in all drug-treated animals. Trabecular bone formation rate (BFR/BS) remained significantly lower than vehicle in bisphosphonate-treated animals through 12 wk. Sixteen weeks after treatment withdrawal, trabecular BFR/BS in the proximal tibia was re-established in animals treated with RIS but not in animals treated with ALN compared with controls. BMD of the fifth lumbar vertebra remained significantly higher than controls 16 wk after treatment withdrawal in ALN-treated animals but not in RIS-treated animals. Despite reductions in BMD and increases in bone turnover, ultimate force of the fifth lumbar vertebra remained significantly higher in all drug-treated animals through 16 wk after withdrawal. [source] | ||||||||||