Novel therapies for osteoporosis.

Since the identification of osteoporosis as a major health issue in aging populations and the subsequent development of the first treatment modalities for its management, considerable progress has been made in our understanding of the mechanisms controlling bone turnover and disease pathophysiology, thus enabling the pinpointing of new targets for intervention. This progress, along with advances in biotechnology, has rendered possible the development of ever more sophisticated treatments employing novel mechanisms of action. Denosumab, a monoclonal antibody against RANKL, approved for the treatment of postmenopausal and male osteoporosis, significantly and continuously increases bone mineral density (BMD) and maintains a low risk of vertebral, non-vertebral, and hip fractures for up to 8 years. Currently available combinations of estrogens with selective estrogen receptor modulators moderately increase BMD without causing the extra-skeletal adverse effects of each compound alone. The cathepsin K inhibitor odanacatib has recently been shown to decrease vertebral, non-vertebral, and hip fracture rates and is nearing approval. Romosozumab, an anti-sclerosin antibody, and abaloparatide, a PTH-related peptide analog, are at present in advanced stages of clinical evaluation, so far demonstrating efficaciousness together with a favorable safety profile. Several other agents are currently in earlier clinical and preclinical phases of development, including dickkopf-1 antagonists, activin A antagonists, ß-arrestin analogs, calcilytics, and Src tyrosine kinase inhibitors.

Circulating irisin in healthy, young individuals: day-night rhythm, effects of food intake and exercise, and associations with gender, physical activity, diet, and body composition.

CONTEXT: The myokine irisin may increase energy expenditure and affect metabolism. OBJECTIVE: The objective of the study was to elucidate predictors of irisin and study whether circulating irisin may have day-night rhythm in humans. DESIGN: This was an observational, cross-sectional study with an additional 24-hour prospective observational arm (day-night rhythm substudy) and two prospective interventional arms (mixed meal substudy and exercise substudy). SETTING: The study was conducted at the Hellenic Military School of Medicine (Thessaloniki, Greece). PATIENTS AND INTERVENTIONS: One hundred twenty-two healthy, young individuals were subjected to anthropometric and body composition measurements, and their eating and exercise behavior profiles were assessed with validated questionnaires. Subgroups were subjected to day-night rhythm, standardized meal ingestion, and 30-minute aerobic exercise studies. MAIN OUTCOME MEASURES: Circulating irisin levels were measured. RESULTS: Ιrisin levels were lower in males than females (P = .02) after adjustment for lean body mass, which was its major determinant. Irisin levels followed a day-night rhythm (P < .001) with peak at 9:00 pm. Irisin levels were increased at the end of exercise (84.1 ± 10.0 vs 105.8 ± 14.3 ng/mL; P < .001). Irisin levels were not affected by intake of a standardized meal and were not associated with caloric intake or diet quality. CONCLUSIONS: In healthy, young individuals, circulating irisin displays a day-night rhythm, is correlated with lean body mass, and increases acutely after exercise.

The role of cytokines and adipocytokines in zoledronate-induced acute phase reaction in postmenopausal women with low bone mass.

OBJECTIVE: Patients treated with intravenous zoledronate frequently experience an acute phase reaction (APR) characterized by flu-like symptoms and increased levels of inflammatory cytokines. We aimed to define the role of various cytokines/adipocytokines in zoledronate-induced APR and develop a prognostic model for its prediction. PATIENTS AND MEASUREMENTS: Fifty-one postmenopausal women with low bone mass were subjected to zoledronate intravenous infusion. Patients were divided into those who experienced APR (APR+) and those who did not (APR-). APR was clinically defined by body temperature and the visual analogue pain scale for musculoskeletal symptoms. White blood cell count, leucocytic subpopulations, C-reactive protein, interleukin-6, tumour necrosis factor-alpha, visfatin, resistin and leptin were measured before and 48 h following the infusion. The quantitative insulin sensitivity check index (QUICKI) and homoeostasis model of assessment - insulin resistance (HOMA-IR) were calculated to assess insulin sensitivity and resistance, respectively. RESULTS: (APR+) patients were younger and had lower baseline visfatin and higher baseline lymphocytes and phosphate compared with APR- patients. QUICKI decreased and HOMA-IR increased in APR+ patients while remained unchanged in APR- patients. In binary logistic regression analysis, a model containing previous bisphosphonate treatment, age, body mass index, lymphocytes and visfatin, which predicted zoledronate-induced APR with 82·1% sensitivity and 73·9% specificity, was selected. In this model, lymphocytes (P = 0·010) and visfatin (P = 0·029) at baseline could independently predict APR. CONCLUSIONS: Zoledronate-induced APR is associated with serum increases of pro-inflammatory cytokines and an increase of insulin resistance. Patients with higher lymphocytes and lower visfatin levels at baseline are at higher risk for APR.

Acute phase response following intravenous zoledronate in postmenopausal women with low bone mass.

An acute phase response (APR) is frequently observed in patients treated with intravenous (i.v.) zoledronate (ZOL). We aimed to define clinical and laboratory parameters that may predict ZOL-induced APR in women with low bone mass. Fifty-one postmenopausal women with low bone mass were given a single i.v. infusion of ZOL 5mg. APR was clinically defined by the visual analog pain scale (VAS) for the musculoskeletal symptoms and body temperature. White blood cell count (WBC), leucocyte subpopulations, C-reactive protein (CRP), parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], interleukins (IL)-1b and -6, tumor necrosis factor (TNF)α and interferon (IFN)γ were measured before and 48 h following the infusion. Subsequently, patients were divided into those experiencing APR (APR+) or not (APR-). WBC, granulocytes, CRP, IL-1b and IL-6 were significantly increased, whereas lymphocytes, eosinophils, calcium, phosphate and 25(OH)D decreased 48h after ZOL infusion. Twenty-eight of the 51 patients (54.9%) experienced an APR. APR+ patients were younger and had higher baseline lymphocytes compared to APR- patients. There was no difference (p=0.405) in the development of APR between treatment-naive patients (19/32, 59.4%) and patients previously treated with another oral nitrogen-containing bisphosphonate (9/19, 47.4%). In conclusion, our data suggest that pre-treatment higher lymphocyte number increases the risk of APR while previous treatment with another nitrogen-containing bisphosphonate does not significantly reduce the risk. Serum 25(OH)D concentrations decrease significantly after the infusion, possibly as part of the inflammatory response to ZOL.

Normochromic normocytic anemia in a postmenopausal woman with severe osteoporosis treated with intermittent parathyroid hormone.

Intermittent exogenous parathyroid hormone (PTH) is a potent osteoanabolic agent used for the treatment of severe osteoporosis. Two molecules of recombinant PTH are commercially available: the full-length PTH (PTH 1-84) and teriparatide (PTH 1-34). We present the first report of PTH-induced mild, asymptomatic, normochromic normocytic anemia in a postmenopausal woman treated sequentially with PTH 1-84 and PTH 1-34. Anemia was more pronounced with PTH 1-84 compared to PTH 1-34 and was reversed with each regimen discontinuation. We suggest monitoring of hematocrit and hemoglobin in PTH-treated patients, especially when PTH 1-84 is used.

Amelioration of cardiovascular risk factors with partial biochemical control of acromegaly.

OBJECTIVE: Complete remission of acromegaly is associated with favourable changes in cardiovascular risk parameters. We evaluated the effects of suboptimal therapy on haemodynamic, metabolic, inflammatory and coagulation cardiovascular risk indices. DESIGN AND METHODS: Eighteen acromegalic patients on somatostatin analogues, with incomplete biochemical control, were evaluated at diagnosis and 6 months after treatment and compared to 15 healthy age- and body mass index (BMI)-matched controls. Measurements of blood pressure, GH, IGF-I, glucose, insulin, glycated haemoglobin (HbA1c), lipids, apolipoprotein A1 (apoA1), apoB, high-sensitivity C-reactive protein (hs-CRP), fibrinogen, plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (tPA) and circulating thrombomodulin were performed in all study participants, followed by an oral glucose tolerance test (OGTT). Insulin sensitivity (IS) was expressed by the Matsuda index (OGTT(ISI)). RESULTS: Partial control of acromegaly resulted in a significant reduction in systolic and diastolic blood pressure, glucose, insulin, HbA1c, total (T-C) and low density lipoprotein cholesterol (LDL-C) and triglyceride levels, and a significant increase in apoA1, high density lipoprotein cholesterol (HDL-C) and OGTT(ISI) compared to pretreatment levels. Plasma fibrinogen and PAI-1 levels fell significantly [respectively (mean +/- SEM), 11.04 +/- 0.41 vs. 10.12 +/- 0.34 micromol/l, P = 0.003 and 9.6 +/- 1.97 vs. 6.55 +/- 1.89 microg/l, P < 0.001]. However, a marked reduction in tPA [median (IQR) 5.1 (2.5-15) vs. 3.4 (2.4-8.6) microg/l, P = 0.031] and an increase in hs-CRP [median (IQR) 0.05 (0.03-0.11) vs. 0.1 (0.06-0.23) mg/l, P < 0.001] were also noted. On treatment, acromegalic patients were comparable to controls, except for OGTT(ISI), lipoprotein(a) [Lp(a)], fibrinogen and tPA and HDL-C levels. Thrombomodulin and apoB levels were not affected by treatment. CONCLUSIONS: Partial control in disease activity following somatostatin analogues results in significant improvement in a considerable number of cardiovascular risk markers in acromegaly.

Osteonecrosis of the jaws due to bisphosphonate use. A review of 60 cases and treatment proposals.

PURPOSE: Bisphosphonates are compounds used in the treatment of various metabolic and malignant bone diseases. In the last two and a half years, there has been a striking increased referral of patients with exposed necrotic jawbone, mostly after several teeth extractions. The only clinical feature common in all patients was the use of bisphosphonates in the treatment of bone diseases. PATIENTS AND METHODS: We performed a retrospective multicentric study of 60 patients with necrotic bone lesions of the jaws of various extent from July 2003 to October 2005. The necrotic bone involved the maxilla (37%), the mandible (50%), or both (13%). The bisphosphonate administered was mostly zoledronate. The management of the patients included cessation of bisphosphonate therapy for more than 6 months, long-term antibiotics, hyperbaric oxygen administration in some cases, and various surgical restorative procedures. RESULTS: The implementation of the treatment protocol in 7 patients so far lead to high cure rates, whereas surgical restoration of the defect without previous cessation of bisphosphonate therapy had discouraging results. CONCLUSIONS: Clinicians and dentists should have in mind this new complication of bisphosphonate administration to identify and treat osteonecrosis of the jaws.