Calcified Tissue International

On 7 patients with mild-to-moderately active Paget's disease, 200 IU of salmon calcitonin (SCT) nasal spray (NS), induced a significant decrease of the total urinary hydroxyproline excretion (THP) during the 8–16 hour and the 0–24 hour (P<0.05) periods after treatment as compared to control day. However, the administration of 100 IU of SCT intramuscularly (i.m.) caused a significantly greater effect than 200 IU-NS during the second 8 hour period after its administration (P<0.01) and on the over-all 24 hour effect (P<0.05). On 3 patients with severe Paget's disease, SCT-NS was essentially ineffective whereas the injection of SCT induced a marked diminution of the THP excretion.

Recent preclinical studies suggest that osteoblasts are able to induce testosterone production by the testis, a process mediated by osteocalcin. Bisphosphonates substantially reduce osteocalcin levels. If osteocalcin is an important regulator of testosterone levels in adult men, it would be expected that the substantial reductions in osteocalcin induced by zoledronate would impact negatively on testosterone levels. Previously, we carried out a 2-year randomized, controlled trial of annual 4 mg zoledronate in 43 HIV-infected men. To explore the relationship between osteocalcin and testosterone further, we measured serum testosterone at baseline, 3 months, and 2 years; luteinizing hormone at 3 months and 2 years; and total osteocalcin at 2 years in 28 trial participants with available blood samples. At 2 years, total osteocalcin was 39 % lower in the zoledronate group than the placebo group (zoledronate mean 10.1 [SD 3.0] μg/L, placebo 16.5 [SD 4.9] μg/L, P = 0.003). Despite these substantial differences in osteocalcin levels, testosterone levels did not change over time in either group and there were no between-group differences over time, P = 0.4 (mean change at 2 years [adjusted for baseline levels] in zoledronate group −0.4 nmol/L, 95 % CI −2.5 to 1.6; placebo group 0.4 nmol/L, 95 % CI −1.6 to 2.5). Luteinizing hormone was within the normal range and did not differ between the groups at either 3 months or 2 years. Thus, the absence of a change in testosterone despite a substantial reduction in osteocalcin following zoledronate treatment argues against a biologically significant role for osteocalcin in the regulation of testosterone in adult men. This provides reassurance that men receiving potent antiresorptive drugs are not at risk of iatrogenic hypogonadism.

The current study is based on our earlier investigation carried out in 1999, where bone mineral density (BMD) of 35 neurofibromatosis type 1 (NF1) patients was measured and osteoporosis was shown to be common in NF1. The findings have been confirmed by a number of later publications. The purpose of the current longitudinal study was to assess the bone health of these 35 NF1 patients 12 years after the initial study. A total of 28 patients were reached, and BMD of 19 patients was subsequently remeasured. Fracture history of 28/35 NF1 patients who were reached was verified from the medical records. Six NF1 patients had osteoporosis in 1999, and three of them had an osteoporotic fracture between 1999 and 2011, showing an increased fracture risk compared to NF1 patients without osteoporosis. BMD of 19 patients was remeasured in 2011, and four patients who had osteopenia in 1999 had osteoporosis in 2011. The decrease in BMD was not explained by changes in smoking habits, physical activity, sunlight exposure, body mass index, or laboratory parameters, even though secondary hyperparathyroidism was common. Osteoporosis was found in 2011 in patients aged 37 years or older, both men and women. The results showed that NF1-related osteopenia often progresses to osteoporosis since BMD decreases with aging even in young patients. Even though our sample size was 19 patients, we recommend follow-up of NF1 patients with osteopenia and consideration of prophylactic measures to prevent osteoporosis and associated fracture risk.

Proteoglycans from bovine nasal septa and from the Swarm rat chondrosarcoma were isolated as aggregates (PGC) and as monomers (PGS). Portions of the PGC preparations were degraded with cathepsin D or chondroitinase AC. Chondroitin sulfates were isolated by differential precipitation from alkaline digests of the PGS from bovine nasal septa. The effects of these preparations at concentrations up to 2 mg/ml on the precipitation of tricalcium phosphatein vitro at pH 7.8 in 16 hours at 25°C were ascertained. To this end, the amounts of calcium and phosphate in the precipitates and in the supernates were determined. The PGC preparations were found to be very effective inhibitors; in the presence of 2 mg/ml, precipitate did not form. The PGS preparations were less effective than the PGC preparations; in the presence of 2 mg/ml, about 20% as much calcium phosphate precipitated as in their absence. The chondroitinase AC-degraded preparations at concentrations equivalent to 2 mg/ml of the PGC preparations were approximately as effective as the PGS preparations. On the other hand, the cathepsin D-degraded PGC preparations and the chondroitin sulfate chains were relatively poor inhibitors. Although the viscosity of the solutions may have influenced the rate at which the precipitates settled to the bottom of the bubes, the amounts of the tricalcium phosphate formed were related to the composition and concentration of the proteoglycan preparations.

In order to determine whether a defect in vitamin D metabolism might play a role in the pathogenesis of X-linked hypophosphatemic rickets and osteomalacia (XLH), we compared the serum 1,25-dihydroxyvitamin D [1,25(OH)2D] level in 52 normal subjects and 37 patients with XLH. In untreated patients, adults were found to have values similar to age-matched controls, while youths had values similar to growth-rate-matched controls but significantly lower than the levels of age-matched controls who were growing at a normal rate. In contrast, treated XLH patients of all ages had serum levels significantly lower than both controls and untreated XLH patients. Further, the serum levels of 1,25(OH)2D in these treated patients had a significant inverse linear correlation with serum 25-(OH)D concentrations. We propose that subjects with XLH have serum 1,25(OH)2D levels within appropriate age- and growth-rate-matched normal ranges. However, in the presence of hypophosphatemia, we would have anticipated elevated levels of 1,25(OH)2D; viewed in this light the serum 1,25(OH)2D levels are inadequate, suggesting the presence of a relative deficiency of this active vitamin D metabolite.

Insulin-dependent type 1 diabetes mellitus (IDDM) has been shown to alter the properties of bone and to impair fracture-healing in both humans and animals. The objective of this study was to examine changes in the histomorphometric and mechanical parameters of bone and remodeling during bone-defect healing, depending on the diabetic metabolic state in spontaneously diabetic BB/O(ttawa)K(arlsburg) rats, a rat strain that represents a close homology to IDDM in humans. A standardized bone-defect model was chosen and based on blood-glucose values at the time of surgery (mg%), postoperative blood-glucose course (mg%), and postoperative insulin requirements (IU/kg). A total of 120 spontaneously diabetic BB/OK rats were divided into groups with a well-compensated (n = 60; 169 ± 102 mg%; 230 ± 126 mg%; and 2.2 ± 1.1 IU/kg) or poorly compensated (n = 60; 380 ± 159 mg%; 359 ± 89 mg%; and 5.4 ± 1.1 IU/kg) metabolic state. Sixty LEW.1A rats served as the normoglycemic controls (93 ± 19 mg%). Fifteen animals from each group were killed on postoperative days 7, 14, 24, and 42, and specimens were processed undecalcified for quantitative bone histomorphometry and for biomechanical testing. Our study showed in terms of bone histomorphometry, within the first 14 days, that severe mineralization disorders occurred exclusively in the rats with a poorly compensated diabetic metabolic state with a highly significant (P < 0.001) or significant (P < 0.01) decrease of all fluorochrome-based parameters of mineralization, apposition, formation and timing of mineralization, as well as significantly decreased values of biomechanical properties (P < 0.05) in comparison to the spontaneously diabetic rats with a well-compensated metabolic state and to the control rats. Bone-defect healing in spontaneously diabetic BB/OK rats is retarded exclusively in a poorly compensated diabetic metabolic state. This study suggests that strictly controlled insulin treatment resulting in a well-compensated diabetic metabolic state will ameliorate the impaired early and late parameters of IDDM bone-defect healing.

An ultrastructural study of peripheral human coronal dentin in patients aged 11 to 75 years, has shown main aspects of the dentinal tubular content. In transverse sections, they consist of dead tracts and annular or solid content to the tubular lumen. No nerve endings were observed in the outer dentin.

Parathyroid hormone (PTH) analogs have a powerful anabolic effect on bone and are used in the treatment of patients with severe osteoporosis. However, there are limitations to how long they can be safely administered. Withdrawal of PTH results in the cancelation of its effects, necessitating subsequent treatment to maintain the bone quantity and quality. This study assessed the effects of Eldecalcitol (ELD), an active vitamin D3 derivative, after PTH in estrogen-deficient osteoporotic rats. Six-month-old female rats were ovariectomized, and PTH administration was started 7 weeks later. After 4 weeks of PTH treatment, the animals were divided into three groups and either continued to receive PTH (PTH–PTH), or were switched to ELD (PTH–ELD) or vehicle (PTH–Veh) for an additional 4 weeks. In the femur, increased BMD by 4 weeks treatment of PTH was significantly reduced in PTH–Veh but not in PTH–PTH and PTH–ELD. The same tendency was observed in the lumbar vertebrae. MicroCT imaging and histomorphometry analysis revealed that the favorable bone structure changes by PTH administration were also maintained in the femurs and tibias of the PTH–PTH and PTH–ELD groups. Increased bone strength by 4-week treatment of PTH in lumber also maintained in PTH–ELD. Furthermore, minimodeling was observed in the PTH–ELD group. These results demonstrate that treatment with ELD sequentially following PTH prevented the bone quantity and strength reduction that accompanies PTH withdrawal in estrogen-deficient rats.

Nitrogen-containing bisphosphonates (N-BPs) inhibit osteoclast-mediated bone resorption and are widely used for tumor-associated osteolysis. The mechanism of action of these drugs has not been completely clarified, but it has been observed that N-BPs may inhibit squalene synthase or farnesyl pyrophosphate synthase. Zoledronic acid (ZA) represents a novel N-BP which also has antitumor activity. To explore the effects of ZA on serum lipids, we studied 26 patients with smoldering myeloma at diagnosis. Sixteen patients were treated with ZA (4 mg) at baseline and at months 1, 2, 4, and 6. The remaining 10 served as controls. In all subjects, total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and C-terminal telopeptide of type I collagen (CTX) were measured at baseline and after 1, 3, and 6 months. In treated patients, we observed a progressive and significant reduction of TC, with a maximum decrease of 13% at 6 months. Moreover LDL-C decreased by 21% at 6 months, while no significant difference was appreciated in HDL-C and TGs. Also, the indexes of cardiovascular risk improved after ZA administration: TC/HDL-C ratio progressively decreased by 17% and HDL-C/LDL-C ratio increased by 36%, showing an effect that appears to be cumulative. In conclusion, ZA given intravenously at high doses in patients with smoldering myeloma seems to be able to modify the lipid profile with an improvement of atherosclerotic risk index.