Review of Treatment Modalities for Postmenopausal Osteoporosis

Extracts of marine algae show inhibitory activity against osteoclast differentiation

Osteoclasts are multinucleated cells that play a crucial role in bone resorption. The imbalance between bone resorption and bone formation results in osteoporosis. Therefore, substances that can suppress osteoclast formation are potential candidate materials for drug development or functional foods. There have been reports that extracts or purified compounds from marine micro- and macroalgae can suppress osteoclast differentiation. Symbioimine, isolated from the cultured dinoflagellate Symbiodinium sp., had suppressive effects against osteoclast differentiation in osteoclast-like cells. Norzoanthamine, isolated from the colonial zoanthid Zoanthas sp., has been shown to have antiosteoporosis activity in ovariectomized mice. With regard to marine extracts, the fucoxanthin-rich component from brown algae has been shown to have suppressive effects against osteoclast differentiation. An extract of Sargassum fusiforme has recently been shown to have antiosteoporosis activity. This extract suppressed both osteoclast differentiation and accelerated osteoblast formation in separate in vitro experiments. It also showed antiosteoporosis activity in ovariectomized mice by regulating the balance between bone resorption and bone formation. These marine algae and their extracts may be sources of marine medicinal foods for the prevention of osteoporosis.

Urinary osteocalcin and other markers of bone metabolism: the effect of risedronate therapy

OBJECTIVE

Serum osteocalcin (S-OC) is widely used as an index of bone formation. However, there is evidence that some urinary fragments of OC reflect resorption and might be useful in monitoring antiresorptive therapy. Here, we report 6-month changes in urinary midfragments of osteocalcin (U-MidOC) and other bone turnover markers in response to risedronate treatment.

MATERIAL AND METHODS

The study group comprised 19 patients with postmenopausal osteoporosis, aged 49-66 years, and receiving risedronate therapy. Fifty-four premenopausal women served as controls. Osteoporosis was diagnosed by lumbal bone mineral density (BMD). Urinary osteocalcin was measured by the U-MidOC assay for midfragments. Bone formation was assessed by S-PINP and S-OC, and resorption by S-CTx-I.

RESULTS

At baseline, U-MidOC was significantly correlated only with S-OC. After the 1st month of therapy, a similar decrease was observed in the values of U-MidOC and S-CTx-I, but in formation markers S-P1NP and S-OC only after three months. The rapid decrease in U-MidOC, analogous to S-CTX-I, and the different kinetics for urinary and serum OC suggest that urinary OC midfragments are more associated with resorption than S-OC. An association was also observed between the 1-month change in U-MidOC and 12-month gain in lumbar BMD. The response in U-MidOC after only the 1st month of therapy makes it a potential marker for monitoring the effect of risedronate, presumably reflecting different aspects of bone resorption than S-CTx-I does.

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.

Redefining osteoporosis treatment: Who to treat and how long to treat

Osteoporosis is a common disease that is associated with increased risk of fractures and serious clinical consequences. Bone mineral density (BMD) testing is used to diagnose osteoporosis, estimate the risk of fracture, and monitor changes in BMD over time. Combining clinical risk factors for fracture with BMD is a better predictor of fracture risk than BMD or clinical risk factors alone. Methodologies are being developed to use BMD and validated risk factors to estimate the 10-year probability of fracture, and then combine fracture probability with country-specific economic assumptions to determine cost-effective intervention thresholds. The decision to treat is based on factors that also include availability of therapy, patient preferences, and co-morbidities. All patients benefit from nonpharmacological lifestyle treatments such a weight-bearing exercise, adequate intake of calcium and vitamin D, fall prevention, avoidance of cigarette smoking and bone-toxic drugs, and moderation of alcohol intake. Patients at high risk for fracture should be considered for pharmacological therapy, which can reduce fracture risk by about 50%.

Addressing and meeting the needs of osteoporotic patients with strontium ranelate: a review

Patients with osteoporosis need a safe and effective treatment that reduces the risk of vertebral and non-vertebral fractures, leading to clinical benefits such as reduced back pain and height loss. Strontium ranelate corrects bone turnover, producing a more physiological state. Double-blind, placebo-controlled studies in postmenopausal osteoporosis show it to be effective in reducing vertebral and non-vertebral fracture risks. Treatment efficacy has been documented across a wide range of patient profiles, and appears to be independent of all the major determinants of fracture risk, including the severity of the disease at baseline, the number of prevalent fractures, and the age of the patient. This antifracture efficacy translates into clinical benefits, such as a 20% reduction in the rate of height loss and a 29% increase in the number of patients free of back pain. The effect of treatment with strontium ranelate on well-being has been assessed using the Quality-of-Life Questionnaire in Osteoporosis, which is a supplement to the 36-question Short-Form Health Survey. Treatment with strontium ranelate had a significant beneficial effect on the emotional, physical, and global Quality-of-Life Questionnaire in Osteoporosis scores compared with placebo. The rates of compliance with treatment were over 80% in phase III studies, reflecting the tolerability and safety profile and the ease of administration of this agent. Together with the antifracture data, the clinical benefits and quality of life data endorse the treatment of postmenopausal osteoporosis with strontium ranelate.