Effects of salmon calcitonin in postmenopausal osteoporosis: a controlled double-blind clinical study

A computational framework and sensitivity analysis for the hormonal treatment of bone

BACKGROUND

Osteoporosis is a bone disease identified by disordering of bone formation and resorption cells. It increases the risk of bone fragility and fracture. Autocrine and paracrine signalling of osteoclasts and osteoblasts plays an important role in the regulation of bone remodelling. Calcitonin is an approved pharmacologic agent for the treatment of osteoporosis.

METHODS

A novel mathematical model comprising the interaction among osteoclasts and osteoblasts cells with intermittent administration of calcitonin has been presented to study the dynamics of osteoporotic bone. The stability of model and sensitivity of parameters are also discussed.

FINDINGS

The population of osteoclastic and osteoblastic cells has been predicted via numerical simulation. The results of Monte Carlo sensitivity analysis are shown via tornado diagram.

INTERPRETATION

It is concluded that intermittent administration of calcitonin is an effective therapy for the treatment of osteoporosis.

Boiled Abalone Byproduct Peptide Exhibits Anti-Tumor Activity in HT1080 Cells and HUVECs by Suppressing the Metastasis and Angiogenesis in Vitro

Abalone (Haliotis discus hannai) is a precious seafood in the market. It has been reported that biological active substances derived from abalone have anti-oxidative, anti-inflammatory, anti-bacterial, and anti-thrombosis potential. However, there were few studies to assess whether they have anti-cancer potential. In this study, we evaluated the anti-metastasis and anti-pro-angiogenic factors and mechanism of action of boiled abalone byproduct peptide (BABP, EMDEAQDPSEW) in human fibrosarcoma (HT1080) cells and human umbilical vein endothelial cells (HUVECs). The results demonstrated that BABP treatment significantly lowers migration and the invasion of HT1080 cells and HUVECs. BABP inhibits phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase (MMP) expression and activity by blocking mitogen-activated protein kinases (MAPKs) and NF-κB signaling and hypoxia-induced vascular endothelial growth factor (VEGF) secretion and hypoxia inducible factor (HIF)-1α accumulation through suppressing the AKT/mTOR signal pathway. BABP treatment inhibits VEGF-induced VEGFR-2 expression and tube formation in HUVECs. The effect of BABP on anti-metastatic and anti-vascular activity in HT1080 cells and HUVECs revealed that BABP may be a potential pharmacophore for tumor therapy in the future.

Bone-seeking agents for the treatment of bone disorders

The targeting and delivery of therapeutic and diagnostic agents to bone tissue presents both a challenge and opportunity. Osteoporosis, Paget's disease, cancer, and bone metastases are all skeletal diseases whose treatment would benefit from new targeted therapeutic strategies. Osteoporosis, in particular, is a very prevalent disease, affecting over one in three women and one in five men in Canada alone with the cost to the healthcare system estimated at over $2.3 billion in 2010. Bone tissue is often considered a rigid structure when in reality there is a process of continuous remodeling that takes place via complex endocrine-regulated cell signaling pathways in addition to the signaling pathways unique to bone tissue. It is these specific boneremodeling processes that provide unique targeting opportunities but also present a number of challenges.

Additive effect of elcatonin to risedronate for chronic back pain and quality of life in postmenopausal women with osteoporosis: a randomized controlled trial

Calcitonin has been reported to reduce acute and chronic back pain in osteoporotic patients. The additive effect of calcitonin with a bisphosphonate on chronic back pain remains unclear. The purpose of this study was to evaluate the effect of combining elcatonin (eel calcitonin) with risedronate for patients with chronic back pain. Forty-five postmenopausal women diagnosed as having osteoporosis with chronic back pain persisting for more than 3 months, after excluding women with fresh vertebral fractures within the last 6 months, were randomly allocated to a risedronate group (risedronate alone, n = 22) and a combined group (risedronate and elcatonin, n = 23). The study period was 6 months. Pain was evaluated with a visual analogue scale (VAS) and the Roland-Morris questionnaire (RDQ). Back extensor strength, bone mineral density, and quality of life on the SF-36 and the Japanese osteoporosis quality of life score were also evaluated. Significant improvements were found in the combined group for VAS at final follow-up compared with baseline and 3 months, mental health status on the SF-36, and JOQOL domains for back pain and general health. The JOQOL domain for back pain improved significantly, but no change was found in the VAS or other domains in the risedronate group. Bone mineral density increased significantly in the two groups, but no significant difference was found between the groups. Back extensor strength did not change in both groups. In conclusion, the use of elcatonin in addition to risedronate for more than 3 months reduced chronic back pain. The additional therapy of risedronate with elcatonin may be a useful and practical choice for the treatment of osteoporosis with chronic back pain persisting more than 3 months.

When the government actively faces the burden of osteoporosis: the Italian experience

EPIDEMIOLOGY AND COSTS OF FRAGILITY FRACTURES IN ITALY: The problem of osteoporosis is emerging as growing phenomenon, with an enormous impact on quality of life and on health expenses. As a consequence, a reduction in the social and health impact of bone fragility would be associated with an improved quality of life of all elderly citizens and with valuable cost savings at the health system level. OSTEOPOROSIS: EVOLUTION OF THE CONCEPT IN ITALY: In the last 20 years, there have been enormous advances in the knowledge of diagnostic and therapeutic options and thus we would be in the position of starting effective therapies in at risk populations. However, this not always happens. NEW APPROACHES TO THE FRAGILITY FRACTURES BY THE ITALIAN GOVERNMENT: In this paper we offer to the reader the possibility to know the history of osteoporosis, its diagnosis and its therapy in Italy, a country where life expectancy is one of the highest in the world. THE FUTURE OF OSTEOPOROSIS IN ITALY: We hope that the example of Italy would serve as an inspiration to those countries where the history of osteoporosis only recently began.

Effect of Dang-Gui-Ji-Hwang-Yeum on Osteoporosis in Ovariectomized Rats

Dang-Gui-Ji-Hwang Yeum (DGJHY; an Oriental prescription), has been successfully used for the management of osteoporotic disorders in China, Japan and Korea. In this study, we have characterized the effect of DGJHY on osteoporosis-associated phenomena in ovariectomized (OVX) rats by measuring body weights and bone histomorphometries in sham, OVX and DGJHY-administered OVX rats. Light microscopic analyses showed a porous or an eroded appearance on the tibial trabecular bone surface in OVX rats, whereas those of the sham and DGJHY-administered OVX rats were composed of fine particles. The trabecular bone area and the trabecular thickness in OVX rats were significantly lower than those of sham rats. Moreover, these reductions in OVX rats were significantly reversed by the administration of DGJHY for 7 weeks, and osteoclast numbers were also significantly reduced. Although no differences were observed between OVX and DGJHY-administered OVX rats and the sham animals at the T 3 level, we have found significant differences between these two groups at the T 4 level. However, serum phosphorus, calcium, mechanical strength and the surface appearance of osteoblasts in the DGJHY-administered OVX rats were similar to those of OVX rats. These results suggest that DGJHY is effective at preventing bone loss in OVX rats.

Progress in osteoporosis and fracture prevention: focus on postmenopausal women

In the past decade, we have witnessed a revolution in osteoporosis diagnosis and therapeutics. This includes enhanced understanding of basic bone biology, recognizing the severe consequences of fractures in terms of morbidity and short-term re-fracture and mortality risk and case finding based on clinical risks, bone mineral density, new imaging approaches, and contributors to secondary osteoporosis. Medical interventions that reduce fracture risk include sufficient calcium and vitamin D together with a wide spectrum of drug therapies (with antiresorptive, anabolic, or mixed effects). Emerging therapeutic options that target molecules of bone metabolism indicate that the next decade should offer even greater promise for further improving our diagnostic and treatment approaches.

Effect of ginseng mixture on osteoporosis in ovariectomized rats

In this study, the authors have characterized the effect of HER-S (red ginseng, Angelicae gigantis Radix, Phyllostachys folium, and soybean extracts) on osteoporosis-associated phenomena in ovariectomized (OVX) rats by measuring body weights and bone histomorphometries in control, sham, OVX, OVX(beta-estradiol-treated), and OVX(HER-S-treated) rats. Light microscopic analyses showed a porous or eroded appearance on the femoral trabecular bone surface in OVX rats, whereas the femoral trabecular bone surfaces of the other groups (control, sham, OVX(17beta-estradiol-treated), and OVX(HER-S-treated) rats) were composed of fine particles. The femoral trabecular bone area and number were decreased in OVX rats, but these reductions were significantly prevented by the administration of HER-S for 7 weeks, similar to estrogen. In the blood biochemistry results, serum phosphorus, calcium, T(3), and T(4) remained unchanged, but blood estrogen levels were significantly increased in HER-S-treated rats, which suggests that estrogen is related to the mechanism of the HER-S-induced antiosteoporosis function in OVX rats.

Salmon calcitonin: a review of current and future therapeutic indications

Salmon calcitonin, available as a therapeutic agent for more than 30 years, demonstrates clinical utility in the treatment of such metabolic bone diseases as osteoporosis and Paget's disease, and potentially in the treatment of osteoarthritis. This review considers the physiology and pharmacology of salmon calcitonin, the evidence based research demonstrating efficacy and safety of this medication in postmenopausal osteoporosis with potentially an effect on bone quality to explain its abilities to reduce the risk of spine fracture, the development of an oral salmon calcitonin preparation, and the therapeutic rationale for this preparation's chondroprotective effect in osteoarthritis.

Osteoporosis

Effective therapies are available for the patient who has arthritic osteoporosis. The approach is critical to ensure an optimal quality of life in these individuals who suffer with a disease that is clearly treatable.

Association of the CT gene (CA) polymorphism with BMD in osteoporotic mexican women

Calcitonin (CT) plays a role in the pathogenesis of osteoporosis and genetic variations in or adjacent to the CT gene may be associated with loss of bone mineral density (BMD). The correlation between a dinucleotide (cytosine-adenine) repeat polymorphism at the CT locus and BMD was examined in 70 osteoporotic women, 70 non-osteoporotic women and 500 subjects from the Mexican population. The allele A and genotype AA frequencies were significantly higher in osteoporotic women than in non-osteoporotic women (60% vs 32%; p < 0.0001 and 41% vs 14%; p = 0.0007, respectively). Genotype AA was associated with the presence of osteoporosis [odds ratio 2.58; 95% confidence interval (CI); 1.62-4.12]. Likewise, the loss of lumbar BMD and T scores were related to the presence of allele A: subjects with a single A allele displayed lower values for lumbar BMD and T score (84.02% and -1.51, respectively) than those who do not present any A allele (89.61% and -0.88, respectively). Individuals with two alleles A showed the lowest lumbar BMD and T-score values (73.77% and -2.51, respectively). Analysis of potential confounder demonstrated that aging has a significant effect on osteoporosis development (odds ratio 1.1; 95% CI; 1.1052-1.152).

Teriparatide vs. calcitonin in the treatment of Asian postmenopausal women with established osteoporosis

This study compared the clinical efficacy, safety, and tolerability of daily subcutaneous injections of teriparatide and salmon calcitonin in the treatment of postmenopausal women with established osteoporosis in Taiwan. This 6-month, multicenter, randomized, controlled study enrolled 63 women with established osteoporosis. They were randomized to receive either teriparatide 20 microg or calcitonin 100 IU daily in an open-label fashion. Lumber spine, femoral neck, total hip bone mineral density (BMD), and biochemical markers of bone turnover were measured, and adverse events and tolerability were recorded. The results at 6 months showed that patients using teriparatide had larger mean increases in spinal BMD than those who used calcitonin (4.5% vs. 0.1%), but the BMD changes in these two groups at the femoral neck and the total hip were not significant. There were also larger mean increases in bone markers in the teriparatide group than in the calcitonin group (bone specific alkaline phosphatase 142% vs. 37%; osteocalcin 154% vs. 23%). We conclude that teriparatide has more positive effects on bone formation than salmon calcitonin, as shown by the larger increments of lumbar spine BMD and bone formation markers, and caused only mild adverse events and no significant change in liver, kidney or hematological parameters. Compared with the published global results, teriparatide seems to be equally effective and safe to use in this Asian population.

Evaluation and management of osteoporosis in liver disease

This article discusses the clinical importance of hepatic osteopenia, the identification of risk factors for the individual patient, and the selection of patients, timing, and methods for diagnostic screening. General supportive measures to maximize bone health should be used in all patients at risk. In addition, for the patient with established osteoporosis, specific therapeutic measures may be justified, despite the lack of adequate randomized trials of these agents in patients with hepatic osteopenia.

Osteoporosis

Bone is a complex organ which contains an organic matrix which serves as scaffolding, includes mineral as calcium distributed in a pattern providing structure and serves as an ion reservoir for the body. Throughout life it dynamically changes in response to changes in activity, body mass, and weight bearing. It is important to define patients at risk for bone loss, since accrued bone loss leading to osteoporosis in the older population of both men and women is unacceptable. There are many different therapies including biphosphonates which can decrease loss of bone and decrease fracture risk in patients who already have had sustained a fracture. Newer therapies such as parathyroid hormone may improve the fracture risk even more than biphosphonates over a shorter period of time.

Tratamiento de la pérdida de masa ósea en la mujer postmenopáusica

In this revision, the results of different controlled clinical trials and metaanalyses on the efficacy in the increase of bone mineral density (BMD) and reduction of risk of fracture on postmenopausal osteoporosis treatments are summarized. Most of the drugs studied produce significant BMD increases but with significant differences regarding fracture risk reduction, especially regarding extravertebral fractures. Bisphosphonates and selective estrogen receptor modulators would constitute the first line of treatment of postmenopausal osteoporosis with previous fractures. Head to head studies would be necessary to know its true efficacy since some results are based on post hoc analysis. Possible side effects, risks, treatment comfort and price in addition to the demonstrated efficacy in fracture prevention must be considered in the selection of treatment.

Effect of intermittent administration of 200 IU intranasal salmon calcitonin and low doses of 1α(OH) vitamin D3 on bone mineral density of the lumbar spine and hip region and biochemical bone markers in women with postmenopausal osteoporosis: a pilot study

A 1-year prospective, open, randomized, controlled trial was conducted as a pilot study to examine the effect of intermittent administration of 200 IU intranasal salmon calcitonin and 1alpha(OH) vitamin D3 [1alpha(OH)D3] on bone mineral density (BMD) of the lumbar spine and hip as well as on the markers of bone metabolism in women with postmenopausal osteoporosis. A total of 102 randomly recruited women received either 200 IU intranasal salmon calcitonin (Miacalcic nasal 200, Novartis, Basel, Switzerland) daily, 1 month on-1 month off, 0.25 mug 1alpha(OH)D3, and 500 mg elemental calcium continuously (n=57 women) or only 0.25 mug 1alpha(OH)D3 and 500 mg calcium (n=45 women) for a period of 1 year. BMD of the lumbar spine and hip plus biochemical markers reflecting calcium (Ca) metabolism and bone turnover [serum Ca, serum phosphorus, intact parathormone (iPTH), total and bone-specific alkaline phosphatase, osteocalcin levels, 24-h urinary Ca, morning fasting urinary Ca/creatinine, and Pyrilinks-D/creatinine ratio] were measured at the beginning of the study before treatment and after 6 and 12 months of treatment. Baseline characteristics of participants, including age, body mass index, lumbar and hip BMD, and biochemical markers were similar between the two groups. A total of 91 patients completed the study (50 in the salmon calcitonin nasal spray group and 41 in the other group). Lumbar BMD increased significantly in the salmon calcitonin group from baseline (3.0%, p=0.005) and in comparison to the non-calcitonin-treated group (p=0.009). The salmon calcitonin group also had a significant increase in femoral neck BMD compared with baseline values (3.1%, p=0.0005) and in comparison to the non-calcitonin-treated group (p=0.0005) in Ward's triangle BMD (2.9% from baseline values, p=0.009) and in comparison to the non-calcitonin-treated group (p=0.005) in trochanteric BMD (3.4% from baseline values, p=0.007) and in comparison to the non-calcitonin-treated group (P=0.01). Urinary Ca/creatinine and Pyrilinks-D/creatinine levels were significantly decreased from baseline in the salmon calcitonin-treated group (-6.1 and -6.3%, respectively, p=0.001). Bone-specific alkaline phosphatase levels were also significantly decreased from baseline in the salmon calcitonin-treated group (-3.6%, p=0.003). In the same group, a significant decrease in iPTH serum levels compared to baseline values (-2.5%, p=0.005) and in comparison to the non-calcitonin-treated group (p=0.005) was noted. In conclusion, in this pilot study, 1-year intermittent treatment with 200 IU intranasal salmon calcitonin and low doses of 1alpha(OH)D3 produced a significant effect on bone turnover and BMD in postmenopausal women with osteoporosis.

Administration of estrogen shortly after ovariectomy mimics the anti-nociceptive action and change in 5-HT1A-like receptor expression induced by calcitonin in ovariectomized rats

Although many clinical reviews are consistent with the view that hormone replacement therapy should be recommended for increasing bone mass of osteoporotic patients, calcitonin administration is preferable to hormone replacement therapy for the alleviation of pain accompanying osteoporosis, despite the fact that osteoporosis and the accompanying pain are accelerated by the reduction in estrogen levels. Distinct from the clinical view, animal studies have shown that estrogen treatment reduces ovariectomy-induced hyperalgesia, although the mechanism of this phenomenon is unknown. The discrepancy in clinical and animal study outcomes may be due to the timing of administration of estrogen after depletion of the hormone. To address this possibility, the anti-nociceptive effect of estrogen was compared with calcitonin using the tail withdrawal test in rats injected with estrogen or calcitonin at 3 weeks (short term) or 15 weeks (long term) after ovariectomy. Furthermore, we analyzed the change in [3H]8-OH-DPAT binding in the spinal cord, addressing whether estrogen exerts its anti-nociceptive effect by the expression of 5-HT receptors attributable to calcitonin-induced analgesia, as has been reported in our previous animal studies. The present study demonstrates that the administration of estrogen injected in the short term, but not long term, after ovariectomy mimicked the effects of calcitonin-induced anti-nociception and prevention of ovariectomy-induced decrease in 5-HT receptor expression in the spinal cord, although the effects of calcitonin were observed regardless of the timing of calcitonin injection. These results suggest that the estrogen receptor is downregulated gradually after ovariectomy. Disappearance of the estrogen receptor may be one of the reasons that estrogen is not recommended for the treatment for chronic pain associated with osteoporosis.

Calcitonin: physiological actions and clinical applications

Calcitonin (CT) was first reported as a hypocalcemic principle, initially thought to originate from the parathyroid gland, a view subsequently corrected to an origin from parafollicular C-cells. Human CT is a 32 amino acid peptide with an N-terminal disulphide bridge and a C-terminal prolineamide residue, shown to potently inhibit bone resorption. More recent studies have demonstrated that this may take place through a direct osteoclastic action. A number of osteoclast CT receptors have subsequently been characterized and particular receptor regions necessary for ligand binding and intracellular signaling identified. Its potent anti-resorptive effect has led to its use in treating Paget's bone disease, osteoporosis, hypercalcaemia and osteogenesis imperfecta. This review summarises some key aspects of its synthesis, structure and its actions at the cellular and molecular levels, and leads on to its therapeutic uses that have emerged since its discovery as well as possibilities for future clinical applications.

Calcitonin

Calcitonin is FDA approved for the treatment of postmenopausal osteoporosis but not for prevention. The preferred delivery system is nasal. Nasal calcitonin is safe and well tolerated. The vertebral fracture efficacy of calcitonin is less robust than the two approved bisphosphonates (alendronate and risedronate) but is similar to raloxifene in the treatment of established osteoporosis. Calcitonin has not been demonstrated to reduce hip fracture risk, although a post-hoc pooled analysis suggests potential effectiveness of nasal calcitonin. Calcitonin produces small increments in bone mass of the spine and modestly reduces bone turnover in women with osteoporosis. Calcitonin may have analgesic benefit in patients with acute painful vertebral fractures. Treatment with calcitonin should be considered for older women with osteoporosis with painful vertebral fractures and for women who fail to respond to or cannot tolerate bisphosphonates. Calcitonin may also be indicated for women who are unable to take bisphosphonates because of impaired renal function.

Evaluation of a soybean product fujiflavone P40 as an antiosteoporotic agent in rats

The preventive effects of Fujiflavone P40 (a soybean isoflavone product) against both bone loss and periodontal alteration were evaluated using an ovariectomized rat model. Rats were divided into five groups: sham-operated (Sham), ovariectomized (OVX), OVX given Fujiflavone P40, OVX given 17beta-oestradiol, and OVX given the vehicle for 17beta-oestradiol, respectively. Fujiflavone P40 contains 46.6% isoflavones which consist of 24.1% daidzin, 16.5% glycitin and 5.9% genistin. Administration of Fujiflavone P40 to OVX rats suppressed the body weight gain until 5 weeks. Fujiflavone P40 also decreased total and high-density lipoprotein (HDL) cholesterols and triglyceride level of OVX rats, significantly. After 7 weeks, Fujiflavone P40 did not recover the coarsened fibre of the periodontal ligament. The ovariectomy decreased the uterine weight by 78%. The administration of 17beta -oestradiol recovered the weight loss by 99%, while Fujiflavone P40 restored it by 33%. The ovariectomy decreased the tibial bone mineral density (BMD) by 22%. The administration of 17beta-oestradiol to OVX rats recovered the tibial BMD decrease by 100%, while Fujiflavone P40 recovered it by 78%. The results suggest that Fujiflavone P40 may be useful as a preventive agent for osteoporosis.

Neutralization of interleukin-11 activity decreases osteoclast formation and increases cancellous bone volume in ovariectomized mice

The issue of whether interleukin-11 (IL-11) contributes to bone loss during states of estrogen deficiency has not been previously determined. We therefore randomized ovariectomized (OVX) mice to once daily interperitoneal injections of either sheep anti-murine IL-11 Ab or normal sheep IgG (NSIgG) for 21 days, and then determined the effects on bone using bone histomorphometry. Here we report that treatment of OVX mice with anti-IL-11 Ab significantly increases both trabecular width and cancellous bone volume. Osteoblast activity, as measured by the percentage of trabecular surface covered by osteoid and rates of bone formation, were also significantly increased following treatment with anti-IL-11 Ab. In contrast, treatment of OVX mice with anti-IL-11 Ab significantly decreased both osteoclast number and activity. Ex-vivo assays of osteoclast formation and activity confirmed the histomorphometric data. Thus, bone marrow cells isolated from anti-IL-11 Ab treated OVX mice formed fewer osteoclasts and resorbed less bone in culture than did marrow cells isolated from either untreated or NSIgG-treated OVX mice. Based on these results we conclude that IL-11 contributes to the bone loss which is observed during states of estrogen deficiency.

Calcitonin: the other thyroid hormone

Calcitonin was originally discovered as a hypocalcemic factor synthesized by thyroid parafollicular C cells. Early experiments demonstrated that calcitonin inhibited bone resorption and decreased calcium efflux from isolated cat tibiae and subsequent histologic and culture studies confirmed the osteoclast as its major site of action. Its potent antiresorptive effect and analgesic action have led to its clinical use in treatment of Paget's bone disease, osteoporosis, and hypercalcemia of malignancy. This review surveys the cellular and molecular basis of these physiologic and clinical actions.

Meta-analyses of therapies for postmenopausal osteoporosis. VI. Meta-analysis of calcitonin for the treatment of postmenopausal osteoporosis

OBJECTIVE

To review the effect of calcitonin on bone density and fractures in postmenopausal women.

DATA SOURCE

We searched MEDLINE and EMBASE from 1966 to 2000 and examined citations of relevant articles and the proceedings of international osteoporosis meetings. We contacted osteoporosis investigators to identify additional studies and primary authors for unpublished data.

STUDY SELECTION

We included 30 studies that randomized women to calcitonin or an alternative (placebo or calcium and/or vitamin D) and measured bone density or fracture incidence for at least 1 yr.

DATA EXTRACTION

For each trial, three independent reviewers assessed the methodological quality and abstracted data.

DATA SYNTHESIS

Calcitonin reduced the incidence of vertebral fractures, with a pooled relative risk (RR) of 0.46 [95% confidence interval (CI) 0.25-0.87, P = 0.02, n = 1404, 4 trials]. However, the RR from the one relatively large randomized controlled trial (RCT) was 0.79 (95% CI 0.62-1.00, P = 0.05, n = 1108). For nonvertebral fractures, the pooled RR was 0.52 (95% CI 0.22-1.23, P = 0.14, n = 1481, 3 trials). Once again, the single large trial showed a less impressive effect than the smaller trials (RR 0.80, 95% CI 0.59-1.09, P = 0.16, n = 1245). For bone density of the lumbar spine, the pooled weekly dose of 250 to 2800 IU per week resulted in significant increase in the weighted mean difference (WMD) of 3.74 (2.04-5.43, P < 0.01, n = 2260, 24 trials). The combined forearm showed a similar effect, with a WMD of 3.02 (95% CI 0.98-5.07, P < 0.01, n = 468, 9 trials). At the femoral neck, the pooled weighted mean difference showed a nonsignificant trend toward benefit, WMD 3.80 (95% CI -0.32-7.91, P = 0.07, 9 trials, n = 513). Methodologically weaker studies tended to show greater effects on bone density, and the lumbar spine results suggested the possibility of publication bias.

CONCLUSIONS

Calcitonin likely increases bone density in postmenopausal women predominantly at the lumbar spine and forearm for weekly doses of greater than 250 IU, although the true effect may be smaller than the pooled estimate would suggest. Calcitonin likely reduces the risk of vertebral fracture; its effect on nonvertebral fracture remains uncertain.

Calcitonin for the long-term prevention and treatment of postmenopausal osteoporosis

Calcitonin is a powerful inhibitor of osteoclast activity that exerts a rapid, transient, and reversible inhibition of bone resorption. Prolonged administration of parenteral calcitonin, by injections of 100 IU every 1 or 2 days, can prevent postmenopausal or postovariectomy bone loss, and is also able to increase trabecular bone mass among patients presenting an established osteoporosis. Prolonged treatment with calcitonin injections is, however, difficult to maintain over the long run. In addition to the ease of administration compared with the injectable forms, nasal calcitonin is much better tolerated, the side effects being rare and generally negligible. A prolonged administration of 200 IU intranasal calcitonin acutely inhibits parameters of bone resorption and can increase lumbar spine bone mineral density (BMD) by 1.7%-3.3% after 1 year. Lower doses also appear to be efficient to prevent early postmenopausal bone loss, but the data are conflictual. The results are more consistent in patients who already suffer from established osteoporosis. The increase in lumbar spine BMD is in the order of 1%-2% after 1 year with 200 IU daily. A therapeutic benefit of calcitonin at the level of the cortical bone has been less well demonstrated than for the trabecular bone. As for other antiosteoporotic therapies, the effect of calcitonin on the reduction of fracture risk has been examined less than the beneficial effect on trabecular bone mass. Currently, there is still no prospective, placebo-controlled study with a sufficient number of patients that demonstrates that long-term parenteral calcitonin administration reduces the risk of osteoporotic fractures. The efficacy of nasal calcitonin treatment to reduce vertebral fracture rate has been best examined in the PROOF (Prevent Recurrence of Osteoporotic Fractures) study. This was a prospective 5-year, placebo-controlled, dose-response study of nasal calcitonin (100, 200, or 400 IU daily). The increase in lumbar spine BMD was modest but significant and not clearly dose dependent, as was the reduction in bone turnover. The relative risk of developing new vertebral fractures was reduced by 33% at the end of the study in the 200-IU dose group (relative risk = 0.67, 95% CI 0.47-0.97, p = 0.03). There was also a nonsignificant reduction in the risk of hip fracture in this dose group. The doses of 100 and 400 IU of calcitonin also reduced the vertebral fracture risk, but the difference did not reach the classical level of statistical significance. A possible effect of calcitonin to enhance bone quality, which cannot be assessed by routinely available methods, is currently being investigated in a prospective placebo-controlled trial that could provide a rational explanation for these effects of calcitonin on the reduction in the vertebral fracture rate without much increase in bone mass or a marked reduction in bone turnover.

Forty years of calcitonin--where are we now? A tribute to the work of Iain Macintyre, FRS

Calcitonin was discovered as a hypocalcemic principal that was initially thought to originate from the parathyroid gland. This view was corrected subsequently, and an origin from the thyroid C cells was documented. The purification and sequencing of various calcitonins soon followed. Calcitonin is a 32-amino-acid-long peptide with an N-terminal disulfide bridge and a C-terminal prolineamide residue. The peptide was shown to potently inhibit bone resorption; however, a direct osteoclastic action of the peptide was confirmed only in the early 1980s. Several osteoclast calcitonin receptors have subsequently been cloned and sequenced. Specific regions of the receptor necessary for ligand binding and intracellular signaling through cyclic AMP and calcium have been identified through systematic deletion mutagenesis and chimeric receptor studies. Calcitonin's potent antiresorptive effect has led to its use in treating Paget's disease of bone, osteoporosis, and hypercalcemia. This review retraces key aspects of the synthesis and structure of calcitonin, its cellular and molecular actions, and its therapeutic uses as they have emerged over the 40 years since its discovery. The review also examines the implications of these findings for future clinical applications as a tribute to early workers to whom credit must be given for creation of an important and expanding field. Notable are the new approaches currently being used to enhance calcitonin action, including novel allosteric activators of the calcitonin receptor, modulation of the release of endogenous calcitonin by calcimimetic agents, as well as the development of oral calcitonins.

Calcitonin

Calcitonin reduces the risk of vertebral fracture in postmenopausal women with osteoporosis. Calcitonin produces small increments in the bone mass of the spine and modestly reduces bone turnover in women with osteoporosis. No significant effect on nonvertebral fractures has been observed. Calcitonin may have analgesic benefit.

Antiosteoporotic activity of Dae-Bo-Won-Chun in ovariectomized rats

The preventive effect of the herbal formulation, "Dae-Bo-Won-Chun" (DBWC), on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. From light microscope analyses, porous or erosive appearances were observed on the surface of trabecular bone of tibia in ovariectomized rats, whereas those of the same bone in sham-operated rats were composed of fine particles. The trabecular bone area and trabecular thickness in ovariectomized rats decreased by 50% from those in sham-operated rats, these decreases were completely inhibited by administration of DBWC at a concentration of 10 mg/kg per day for 7 weeks. The mechanical strength of the neck of the femur was decreased by ovariectomy, and this was significantly suppressed by the administration of DBWC. Serum phosphorus, alkaline phosphatase and thyroxine levels in ovariectomized rats increased compared with those in sham-operated rats, and increases were completely inhibited by the administration of DBWC. These results strongly suggest that DBWC is effective in preventing the development of bone loss induced by ovariectomy in rats.

A controlled trial of calcitonin therapy for the prevention of post-liver transplantation atraumatic fractures in patients with primary biliary cirrhosis and primary sclerosing cholangitis

BACKGROUND/AIMS

Accelerated bone loss occurs early after liver transplantation (OLT) and, in cholestatic patients with pre-existing osteopenia, causes spontaneous fracturing. This study aimed to investigate the efficacy of calcitonin, a powerful inhibitor of bone resorption, in preventing or reducing the accelerated rate of bone loss and fracturing which occurs in patients with primary biliary cirrhosis and primary sclerosing cholangitis early after OLT.

METHODS

Sixty-three patients undergoing OLT for primary biliary cirrhosis (n = 26) and primary sclerosing cholarigitis (n = 37) were randomized to receive: (a), 100 IU/day of salmon calcitonin subcutaneously for the first 6 months posttransplant; or (b), no therapy. At pretransplant, and at 4 and 12 months after OLT, patients were investigated clinically, biochemically, by bone mineral density of the lumbar spine, and by radiographs of the thoracolumbar spine, chest and site of any bone pain.

RESULTS

The bone mineral density of the lumbar spine fell equally at 4 months in both groups, from 0.85 to 0.81 g/cm2 in calcitonin-treated patients (n = 29) and from 0.88 to 0.82 g/cm2 in controls (n = 34); at 12 months, both groups had stabilized to 0.83 g/cm2. Fracturing was the same in both groups.

CONCLUSIONS

Calcitonin therapy for the first 6 months after OLT is unable to prevent or reduce accelerated bone loss or spontaneous fractures which occur in the first posttransplant year.

Alterations in the periodontium after ovariectomy in rats: the effects of a Japanese herbal medicine, Chujo-to

Ovariectomy-induced changes on the periodontium (gingiva, alveolar bone, and periodontal ligament) in rats and the preventive effects of a Japanese herbal medicine, Chujo-to, were studied for a period of 49 days. The rats were divided into five groups: sham-operated (sham), ovariectomized (OVX), OVX given Chujo-to, OVX given 17beta-oestradiol, and OVX given the vehicle for 17beta-oestradiol, respectively. After the test period, the bone mineral content (BMC) of the mandibular condyle in OVX rats was similar to those in both sham rats and the OVX rats treated with either Chujo-to or 17beta-oestradiol. However, the scanning electron microscopic (SEM) analyses revealed that the periodontal ligament of the OVX rats and the OVX rats treated with Chujo-to became more coarse than that of the sham rats or the rats treated with 17beta-oestradiol. The surface of the alveolar bone in the OVX rats appeared to contain numerous small granules, which were not present in the sham rats and the rats treated with either Chujo-to or 17beta-oestradiol. These results suggest that ovariectomy caused alterations in the peridontium, but Chujo-to had a preventive effect on the surface architecture of the alveolar bones.

Use of calcitonin for the treatment of an odontoid fracture. Case report

The authors report on the efficacy of nonsurgical treatment of an older patient with a fractured odontoid process. The patient, an 85-year-old woman, had multiple medical problems that put her at an increased surgery-related risk. Therefore, an alternative approach was elected, including immobilization with a Philadelphia collar and the provision of calcitonin nasal spray. Bone union and clinical recovery were achieved within 8 weeks of initiating the nasal calcitonin therapy (12 weeks postinjury). Considering the patient's age, comorbidities, and the severity of the fracture, the recovery period was unusually short. The authors believe that calcitonin played a pivotal role in the healing process of the fractured odontoid bone. There is no question that the fusion in this patient could be unrelated to the medical therapy. This description of one patient, as well as the lack of a large randomized study, precludes any scientific conclusions. Nevertheless, the authors believe that the development of a successful fusion in this high-risk patient should be reported as an observation that merits confirmation and study. The authors also discuss the physiological effects of calcitonin and the research and clinical experience with this hormone in different conditions affecting bone.

Prevention and treatment of osteoporosis: efficacy of combination of hormone replacement therapy with other antiresorptive agents

Osteoporosis is a debilitating disease characterized by decreased bone mineral density (BMD) leading to fractures. It primarily affects postmenopausal women and elderly men. Prevention of osteoporosis is very important because present therapies do not have the potential to mend damage to the bone microarchitecture caused by osteoporosis. The first line of prevention and treatment of osteoporosis is hormone replacement therapy (HRT). All of the approved drugs for the prevention and treatment of osteoporosis act as inhibitors of bone resorption; these drugs include HRT, selective estrogen receptor modulators, calcitonin, and bisphosphonates. The latter two drugs have also been shown to prevent fractures. This article discusses data from nine controlled prospective clinical studies. Study 1 was designed to assess the efficacy of combined HRT and bisphosphonate in preventing osteoporosis during the early stages of menopause. This combined therapy increased the lumbar spine BMD by 10.9% and femoral BMD by 7.3% over 4 yr, compared with 6.8 and 4.0% with HRT alone, and 6.8 and 1.2% with bisphosphonate alone. Study 2 was conducted on postmenopausal women with established osteoporosis. These results showed a 10.4 and 7.0% increase in BMD in vertebrae and femora, respectively, compared with 7.3 and 4.8% increases in the HRT group, and 6.8 and 0.9% in the bisphosphonate group. Data from study 3 demonstrated similar findings in that the combination of alendronate and HRT also enhanced BMD values. Studies 4 and 5 assessed the efficacy of the combined therapy of HRT and calcitonin in the prevention of early postmenopausal bone loss. Both studies demonstrated a significant increase in BMD over and above that observed with either HRT or calcitonin alone. Studies 6, 7, and 8 demonstrated that the addition of testosterone to estrogen therapy further increased BMD when compared to estrogen therapy alone, and also prevented the expected decreases in markers of bone formation in early postmenopausal women. Study 9 demonstrated a synergistic effect on BMD in postmenopausal women, when HRT was coadministered with monofluorophosphate. Other combination therapies may also enhance BMD (e.g., the combination of alendronate and parathyroid hormone [PTH]). However, some agents either lose their efficacy or have no added effects on BMD when they are coadministered (e.g., tiludronate and PTH, calcitonin and PTH, calcitonin and anabolic steroids). These studies illustrate that in a subgroup of patients (i.e., patients with high bone turnover and/or severe osteoporosis), specific combination treatments such as HRT with bis-phosphonates, calcitonin, or androgens (and perhaps also with PTH, fluoride, nitric oxide donors) provide additional beneficial effects over a single-drug therapy. Whether these combination therapies are more effective than individual drugs in reducing fractures still needs to be determined.

The role of calcitonin in the prevention of osteoporosis

This article discusses calcitonin as an alternative for patients with established osteoporosis who cannot, will not, or should not proceed with estrogen replacement therapy. Clinical trial data for calcitonin in both injectable and nasal spray formulations and for both lower-dose and higher-dose regimens are presented.

Osteoporosis

Osteopenia, in the form of osteoporosis, is a common complication of chronic cholestatic liver diseases and, although its cause is poorly understood, it appears to be intimately related to the cholestasis itself. With more patients surviving longer with successful liver transplantation, the clinical significance of such osteopenia has increased, and a traumatic fracturing has become a major cause of morbidity in this patient population. Noninvasive diagnosis is easy, and serial measurements allow assessment of disease progression. Although no effective therapy can treat or prevent this complication, supportive measures can improve skeletal well-being, especially in high-risk individuals who are candidates for liver transplantation.

Effects of nasal administration of calcitonin in oophorectomized women: 2-year controlled double-blind study

OBJECTIVE

The aim of this study was to assess the effects of nasal salmon calcitonin (SCT) administration on bone turnover in ovariectomized women.

METHODS

Patients who had undergone bilateral ovariectomy 7 days previously, received either calcium supplementation (1000 mg/day, together with nasal SCT (100 IU/day) (n = 19) or the same calcium supplementation together with a placebo intranasal spray daily (n = 19), for 2 years.

RESULTS

In the calcium-only-treated subjects, lumbar bone mineral density (BMD) was found to have decreased significantly (P < 0.001), 6 months after surgery and remained at this level until the end of the study. In the SCT-treated group, BMD remained stable during the 1st year and then decreased gradually, reaching a statistically significant level in the 2nd year. Mean serum osteocalcin concentration was unchanged during the 1st year of SCT treatment but was significantly elevated during the 2nd year (P < 0.01). The observed rise in serum osteocalcin concentration and urinary hydroxyproline excretion during the 2nd year of treatment with SCT was accompanied by a significant rise in serum calcitonin levels (P < 0.001 after 18 months and P < 0.01 after 24 months).

CONCLUSION

This study shows that continuous treatment with intranasal SCT is able to prevent the bone loss that follows ovariectomy.

Effect of medication on biomechanical properties of rabbit bones: heparin induced osteoporosis

The aim of this controlled study is to investigate the effect of heparin on osteoporosis initiation and of calcitonin and tamoxifen on the progress of osteoporosis induced by heparin through biomechanical means and, thus, to assist in clinical usage of these drugs. 32 four-month-old female New Zealand white rabbits were divided into four different experimental groups. The animals in group A were administered heparin (Liquemine) intraperitoneally at the dosage of 1000 IU/kg/day. The animals in group B were injected the same amount of heparin as those of group A, and in addition, were given calcitonin at the dosage of 100 IU/kg/day. The animals in group C were medicated the same way as group B but 2 mg/kg/day tamoxifen (Nolvadex) was orally added into their intestine via cannula, one side connected to the injector. The animals in group D were the control. The experiment lasted 8 weeks. The animals in all experimental groups showed the same growth pattern as that of the control group. Whole-bone femur, humerus and tibia specimens were subjected to 3-point bending tests while sections from the proximal ends of the same specimens were subjected to compression tests. The data, recorded as load vs deflection, were converted into stress vs strain using the strength of materials formulae. The data obtained from the bending and the compression experiments were treated separately. The stiffness of the bones of the medicated groups were compared with those of the control groups. Our data indicated that the tamoxifen treated humera, femora and tibiae attained the largest bending stiffness in all cases investigated. However, this was not the case for compression. None of the drug administered groups attained the stiffness of the control group except for the case of tamoxifen treated femora which attained stiffness close to that of the controls. The results show that heparin altered the mechanical properties of bones indicating osteoporosis, tamoxifen was effective in reducing the effect of heparin while calcitonin yielded no conclusive result.

Calcitonin alters bone quality in beagle dogs

Because of its antiresorptive properties, calcitonin is widely used to prevent and treat osteoporosis. A stimulatory effect of calcitonin on osteoblasts has also been reported; however, a recent histologic study points to a negative effect of calcitonin on mineralization of cancellous bone. The present experiment was performed to determine whether the observed histological signs of alterations in mineralization are also observed in cortical bone and whether this results in changes in mechanical properties, mineral densities, or mineral properties of canine bone. Sixteen female adult beagle dogs were randomly allocated to receive either human calcitonin at a dose of 0.25 mg/dog (50 IU, n = 8) or vehicle (mannitol, n = 8) every other day for 16 weeks. At the end of the study, the dogs were euthanized. Both tibiae, L1 and L5 vertebrae, and iliac crest bone samples were excised and defleshed. Torsional mechanical properties of tibial diaphyses and compressive strengths of vertebrae were measured. Bone mineral densities (BMD) of tibiae and vertebrae were measured by using dual-energy X-ray absorptiometry. Ultrastructural mineral characteristics of iliac crest bone were determined by gravimetry and Fourier transform infrared spectroscopy (FTIR). Bone histomorphometry was performed in the cortical envelope of the iliac crest. Tibiae from dogs treated with calcitonin withstood significantly less maximum torque until failure, required less torsional energy to reach the maximum torque, and had less torsional stiffness than the tibiae from dogs treated with vehicle (p < 0.05). Cancellous cores of vertebrae from calcitonin-treated dogs withstood less compressive mechanical loading than did vertebral cores from vehicle-treated animals (p < 0.05). Dogs treated with calcitonin had less BMD of both tibiae and vertebrae than vehicle-treated animals (p < 0.05). Bones from calcitonin-treated dogs had significantly less ash content, which correlated with the lower phosphate-to-amide I (detected by FTIR) and greater carbonate-to-phosphate ratios than did bones from vehicle-treated dogs (p < 0.05). Calcitonin-treated dogs exhibited a decrease in bone formation and mineralization rates and an increase in mineralization lag time. These results point to a negative effect of calcitonin on bone quality. These findings are intriguing and call for further studies addressing whether the observed abnormalities are transient or permanent.

A double blind study of intranasal calcitonin for established postmenopausal osteoporosis

Intranasal administration of calcitonin (CT) avoids the problem of daily injections in the long-term treatment of osteoporosis. We examined the effect of nasal CT on bone and calcium metabolism in postmenopausal osteoporotic women in a double-blind design. 46 women, 55-75 years in age, and in good general health were included in the study. All patients were at least 6 months postmenopausal and had at least 1 vertebra fracture, bone mineral density (BMD; g/cm2) lower than 0.850 in L2-L4 in a dual energy x-ray absorptiometry (DEXA) AP view of the spine and showed biochemical indications of a fast bone loser. The patients were randomly treated with either nasal CT 200 IU per day, divided in 2 doses (n = 23) or placebo (n = 23) for 1 year. All participants received a daily calcium supplement of 1 g. Clinical and laboratory follow-up every 3 and 6 months, respectively, assessed the clinical picture, bone mineral density measured by DEXA, serum alkaline phosphatase, fasting urinary calcium, creatinine and hydroxyproline. BMD was measured in 4 sites (spine and cervical, Ward's triangle, and the trochanteric area of the hip) before treatment and after 6 and 12 months of treatment. In the placebo group, mean values at the 4 sites showed a 3.3% decrease in BMD after 6 months and a 5.0% decrease after 12 months. In contrast, the calcitonin group showed a 6.8% increase in BMD after 6 months and 11% increase after 12 months (p < or = 0.005). No patient experienced side-effects and there were no complaints of local irritation. We conclude that nasal administration of 200 IU calcitonin daily, continuously for 1 year had a positive effect on the bone mass density in osteoporotic postmenopausal women.

Calcitonin versus etidronate for the treatment of postmenopausal osteoporosis: a meta-analysis of published clinical trials

This review examines the evidence on the efficacy of calcitonin and etidronate in the prevention of osteoporosis and osteoporotic fractures. MEDLINE was searched for clinical trials calcitonin or etidronate and reviews of the treatment of postmenopausal osteoporosis. The reference sections of the papers retrieved were again searched for trials on the treatments of interest. Two people independently collected data from the trials that met the inclusion criteria of the study. Weighted means in the change in bone mineral density (BMD) and differences in vertebral fracture rates were computed for calcitonin and etidronate separately. The existence of publication bias was investigated by funnel plots of effect size against sample size. Eighteen clinical trials and calcitonin and six with etidronate were included in the meta-analysis. The pooled change in vertebral BMD at the end of the studies was 1.97 (95% CI 1.77 to 2.17) with calcitonin and 3.20 (95% CI 2.92 to 3.48) with etidronate. Pooled change in proximal femur BMD was 0.32 (95% CI -0.27 to 0.91) with calcitonin and 2.42 (95% CI 2.16 to 2.68) with etidronate. The aggregated number of vertebral fractures prevented by the treatment was 59.2 per 1000 patient-years (95% CI 55.1 to 63.3) for calcitonin and 28.3 (95% CI 26.2 to 30.4) for etidronate. With the available evidence we cannot establish the superiority of either of the two drugs for the treatment of postmenopausal osteoporosis. The clinical trials are particularly lacking in data on hip fracture, the most important consequence of osteoporosis. In this situation consideration of the relative costs of the drugs is prominent.

Effect of three years of oral alendronate treatment in postmenopausal women with osteoporosis

OBJECTIVE

Oral alendronate sodium is a potent, specific inhibitor of osteoclast-mediated bone resorption. To assess its efficacy and safety, a 3-year, randomized, double-blind, multicenter study of 478 postmenopausal women with osteoporosis was conducted.

PATIENTS AND METHODS

Subjects received either placebo, alendronate 5 or 10 mg/day for 3 years, or 20 mg/day for 2 years followed by 5 mg/day for 1 year (20/5 mg). All subjects received 500 mg/day of supplemental calcium. Bone mineral density (BMD) was measured by dual energy x-ray absorptiometry (DXA).

RESULTS

After 3 years, alendronate 10 mg induced marked increases in BMD of the lumbar spine (9.6 +/- 0.4%), femoral neck (4.7 +/- 0.7%) and trochanter (7.4 +/- 0.6%) (mean +/- SE; each P < or = 0.001) versus decreases of 0.8 to 1.6% with placebo. Progressive increases at these sites in the alendoronate 10 mg group were significant during both the second and third years. Alendronate 10 mg increased total body BMD (1.6 +/- 0.3%, P < or = 0.001), and prevented loss but did not increase BMD at the 1/3 forearm site. Alendronate 20/5 mg was no more effective, whereas alendronate 5 mg was significantly less effective than 10 mg at all sites. Bone turnover decreased to a stable nadir over 3 months for resorption markers (urine deoxypyridinoline) and over 6 months for formation markers (alkaline phosphatase and osteocalcin). Mean loss of stature was reduced by 41% in alendronate treated subjects (P = 0.01).

CONCLUSION

The safety profile of alendronate was similar to that of placebo. At 10 mg, there were no trends toward increased frequency of any adverse experience except for abdominal pain, which was usually mild, transient, and resolved with continued treatment. Thus, alendronate appears to be an important advance in the treatment of osteoporosis in postmenopausal women.

Salmon calcitonin nasal spray : An effective alternative to estrogen therapy in select postmenopausal women

The efficacy and safety of estrogen replacement therapy (ERT) and salmon calcitonin in the treatment of postmenopausal osteoporosis are reviewed with special consideration given to patients for whom ERT, the primary antiresorptive therapy for osteoporosis, is not indicated, tolerable, or is refused. The various formulations of estrogen and salmon calcitonin, for which the nasal spray formulation was recently approved for use in the United States, are reviewed in depth with reference to dose ranges, side effects, and convenience. Data regarding increases in bone mineral density (BMD) produced by each agent are presented. Specifically, the range of increases in BMD induced by ERT and salmon calcitonin are comparable. Given the substantial public health consequences of postmenopausal osteoporosis and osteoporotic fractures, the primary care physician is increasingly faced with the need to educated and recruit postmenopausal patients to appropriate therapy with the optimal agent for that particular patient. In the many patients who are unable or unwilling to accept, initiate, and comply with prescribed ERT, alternative therapeutic options are necessary Based on the established safety profile of salmon calcitonin, ease of administration, an uncomplicated dosing regimen, no reported drug interactions, and the lack of uterine bleeding associated with ERT or gastrointestinal adverse effects of other agents used to treat osteoporosis, salmon calcitonin nasal spray is an appropriate alternative approach for the treatment of postmenopausal bone loss.