Efficacy data on teriparatide (parathyroid hormone) in patients with postmenopausal osteoporosis

Personalized Therapeutic Strategies in the Management of Osteoporosis in Patients with Autoantibody-Positive Rheumatoid Arthritis

Bone mineral density (BMD) reduction and fragility fractures still represent a major source of morbidity in rheumatoid arthritis (RA) patients, despite adequate control of the disease. An increasing number of clinical and experimental evidence supports the role of autoantibodies, especially anti-citrullinated protein antibodies (ACPAs), in causing localized and generalised bone loss in ways that are both dependent on and independent of inflammation and disease activity. The human receptor activator of nuclear factor kappa B and its ligand—the so-called RANK-RANKL pathway—is known to play a key role in promoting osteoclasts’ activation and bone depletion, and RANKL levels were shown to be higher in ACPA-positive early untreated RA patients. Thus, ACPA-positivity can be considered a specific risk factor for systemic and periarticular bone loss. Through the inhibition of the RANK-RANKL system, denosumab is the only antiresorptive drug currently available that exhibits both a systemic anti-osteoporotic activity and a disease-modifying effect when combined with conventional synthetic or biologic disease-modifying anti-rheumatic drugs (DMARDs). Thus, the combination of DMARD and anti-RANKL therapy could be beneficial in the prevention of fragility fractures and structural damage in the subset of RA patients at risk of radiographic progression, as in the presence of ACPAs.

Loading-related regulation of transcription factor EGR2/Krox-20 in bone cells is ERK1/2 protein-mediated and prostaglandin, Wnt signaling pathway-, and insulin-like growth factor-I axis-dependent

Of the 1,328 genes revealed by microarray to be differentially regulated by disuse, or at 8 h following a single short period of osteogenic loading of the mouse tibia, analysis by predicting associated transcription factors from annotated affinities revealed the transcription factor EGR2/Krox-20 as being more closely associated with more pathways and functions than any other. Real time quantitative PCR confirmed up-regulation of Egr2 mRNA expression by loading of the tibia in vivo. In vitro studies where strain was applied to primary cultures of mouse tibia-derived osteoblastic cells and the osteoblast UMR106 cell line also showed up-regulation of Egr2 mRNA expression. In UMR106 cells, inhibition of β1/β3 integrin function had no effect on strain-related Egr2 expression, but it was inhibited by a COX2-selective antagonist and imitated by exogenous prostaglandin E2 (PGE2). This response to PGE₂ was mediated chiefly through the EP1 receptor and involved stimulation of PKC and attenuation by cAMP/PKA. Neither activators nor inhibitors of nitric oxide, estrogen signaling, or LiCl had any effect on Egr2 mRNA expression, but it was increased by both insulin-like growth factor-1 and high, but not low, dose parathyroid hormone and exogenous Wnt-3a. The increases by strain, PGE2, Wnt-3a, and phorbol 12-myristate 13-acetate were attenuated by inhibition of MEK-1. EGR2 appears to be involved in many of the signaling pathways that constitute early responses of bone cells to strain. These pathways all have multiple functions. Converting their strain-related responses into coherent “instructions” for adaptive (re)modeling is likely to depend upon their contextual activation, suppression, and interaction probably on more than one occasion.

Drug combination strategies for osteoporosis

Several medications are effective in reducing the incidence of osteoporotic fractures. Vertebral and nonvertebral fractures can be reduced by 30-65% by administering anticatabolic agents (e.g. raloxifene, alendronate, and risedronate) or anabolic agents (e.g. the active parathyroid hormone fragment teriparatide and strontium ranelate). These medications were investigated in placebo-controlled randomized trials in vast populations. Study extensions provided information on long-term efficacy and safety. However, the best strategy for using these medications in high-risk individuals remains unclear. For instance, the relative merits of starting with an anabolic agent or on an anticatabolic agent have not been compared. The patient's age, severity of the osteoporosis (bone mineral density and risk factor profile), specific characteristics of each medication, and patient preferences regarding drug-dosing modalities should be considered. Compliance must be evaluated regularly. Whereas minimal treatment durations have been determined, optimal durations remain incompletely evaluated and should be determined on a case-by-case basis according to the severity of the bone disease and to the treatment response in terms of clinical features and bone mineral density. Synchronous and t treatment combinations have been evaluated. Disappointing results were obtained with synchronous parathyroid hormone and bisphosphonate therapy. In contrast, the parathyroid hormone-bisphosphonate sequence holds promise for the treatment of severe postmenopausal osteoporosis with at least two vertebral fractures. However, little is known about potential synergies among medications in terms of fracture risk reduction. Synchronous and sequential regimens have not been compared in randomized clinical trials, and such trials would be extraordinarily difficult to design. Nevertheless, available data allow a number of suggestions regarding treatment strategies. The most important step is deciding to start effective treatment (raloxifene, bisphosphonate, teriparatide, or strontium ranelate) in patients at risk for fractures. Patients should be given detailed information on potential benefits and long-term treatment modalities.

Anabolic Agents: A New Chapter in the Management of Osteoporosis

Osteoporosis in postmenopausal women has until now been treated with antiresorptive agents, reducing the incidence of fragility fracture by approximately 50%. Clinical research has led to the development of new anabolic therapies capable of increasing the production of bone matrix by osteoblasts and reversing microarchitectural deterioration, resulting in major improvements in both bone quality and bone quantity. Teriparatide, a recombinant human parathyroid hormone consisting of the first 34 of 84 amino acids in human parathyroid hormone, has been shown to reduce significantly the risk of both vertebral and non-vertebral fractures in postmenopausal women. This agent was recently approved for use in Canada. Strontium ranelate is a new oral agent capable of uncoupling bone resorption from bone formation, which results in increases in bone formation with reductions in bone resorption. This agent has also been shown to reduce the risk of both vertebral and non-vertebral fracture while improving bone structure. Anabolic therapies represent a major advance in the management of postmenopausal osteoporosis, and they may provide significant benefit to those patients with severe osteoporosis in whom antiresorptive therapy has proven insufficient. Anabolic therapies should complement the antiresorptive treatments currently available for use in women with postmenopausal osteoporosis.

Hormone replacement therapy in women with spinal cord injury – a survey with literature review

STUDY DESIGN

Postal questionnaire survey.

OBJECTIVE

To examine the current use of hormone replacement therapy (HRT) in a sample of menopausal women with spinal cord injury (SCI).

SETTING

National Spinal Injuries Centre (NSIC), Stoke Mandeville Hospital, Aylesbury, UK.

METHOD

A postal questionnaire was sent to 94 women from the NSIC patient database who met the study inclusion criteria (wheelchair dependent, aged 49 years and above, last seen or heard from within the last 3 years).

RESULTS

A total of 59 valid questionnaires were analysed. At the time of the survey, 50 women were menopausal and 11 of them were using HRT, six for menopausal symptoms and five for osteoporosis prevention. Another 11 had used HRT, eight for menopausal symptoms and three for osteoporosis prevention, but had discontinued it. The main reasons for stopping HRT were side effects. Of the 28 women who had never been on HRT, 20 had either enquired about it, or had been offered HRT, but decided against it. Of the nine women who were still premenopausal at the time of the survey, four would consider using HRT.

CONCLUSIONS

Results show that 44% of the menopausal women in our sample have used HRT at some point and 22% still do, mostly for treatment of menopausal symptoms and for osteoporosis prevention. In view of the latest literature findings in able-bodied women, use of HRT for osteoporosis prevention in women with SCI may have to be reconsidered.