Effects of competitive physical activity on serum irisin levels and bone turnover markers.

BACKGROUND: Irisin, a myokine, is a polypeptide derived from the cleavage of the extracellular domain of fibronectin domain-containing protein 5, a receptor that is present on different tissues (skeletal muscle, pericardium, myocardium, and brain), whose functions are not yet fully defined. PURPOSE: The main aim of our study was to evaluate the effect of competitive physical activity on serum irisin levels and bone turnover markers. METHODS: Fifteen male footballers and an equal number of subjects of the same age and gender, but with a predominantly sedentary lifestyle, had their serum levels of irisin and bone turnover markers measured. Bone mineral status was evaluated in both groups by quantitative bone ultrasound of the calcaneus. In addition, only in footballers, biochemical analyses were repeated after 3 months. RESULTS: We did not observe significant differences in the serum levels of calcium, phosphorus, and parathyroid hormone between the two groups. The footballers had significantly higher quantitative bone ultrasound, 25-OH vitamin D, and creatinine values than the controls. There were also no significant differences in the bone alkaline phosphatase, carboxy-terminal telopeptide of type I collagen, osteoprotegerin, sclerostin or Dkk-1 values, while the irisin levels (+ 89%, p < 0.001) and RANKL were significantly higher in the footballers compared to those in the controls. CONCLUSION: Our study shows that footballers have significantly higher serum irisin values than the general population. Irisin could be the "trait d'union" between bone health and physical activity.

Quantitative ultrasound and DXA measurements in aromatase inhibitor-treated breast cancer women receiving denosumab.

PURPOSE: Denosumab has been proven to reduce fracture risk in breast cancer (BC) women under aromatase inhibitors (AIs). Quantitative ultrasound (QUS) provides information on the structure and elastic properties of bone. Our aim was to assess bone health by phalangeal QUS and by dual-energy X-ray absorptiometry (DXA), and to evaluate bone turnover in AIs-treated BC women receiving denosumab. METHODS: 35 Postmenopausal BC women on AIs were recruited (mean age 61.2 ± 4.5 years) and treated with denosumab 60 mg administered subcutaneously every 6 months. Phalangeal QUS parameters [Amplitude Dependent Speed of Sound (AD-SoS), Ultrasound Bone Profile Index (UBPI), Bone Transmission Time (BTT)] and DXA at lumbar spine and femoral neck were performed. Serum C-telopeptide of type 1 collagen (CTX) and bone-specific alkaline phosphatase (BSAP) were also measured. The main outcomes were compared with a control group not receiving denosumab (n = 39). RESULTS: In patients treated with denosumab, differently from controls, QUS and DXA measurements improved after 24 months, and a reduction of CTX and BSAP was detected at 12 and 24 months in comparison to baseline (P < 0.05). The percent changes (Δ) of QUS measurements were significantly associated with ΔBMD at femoral neck, and ΔCTX and ΔBSAP were associated with ΔBMD at lumbar spine (r = -0.39, P = 0.02; r = -0.49, P = 0.01, respectively). CONCLUSIONS: Denosumab preserves bone health as assessed by phalangeal QUS and DXA. Since inexpensive and radiation-free, phalangeal QUS may be considered in the follow-up of AIs-treated BC women receiving denosumab.

Bisphosphonates in the treatment of thalassemia-associated osteoporosis.

Thalassemia major is a common cause of skeletal morbidity, as shown by the increased fracture risk in thalassemic patients. The etiology of this bone disease is multifactorial and culminates in a state of increased bone turnover with excessive bone resorption and remodeling. Despite hormonal replacement therapy, calcium and vitamin D administration, effective iron chelation, and normalization of hemoglobin levels, patients with thalassemia major continue to lose bone mass. The increased bone turnover rate observed in thalassemic patients justifies the use of powerful anti-resorption drugs, such as bisphosphonates. To date, alendronate, pamidronate, and zoledronate seem to be effective in increasing bone mineral density and normalizing bone turnover, but more trials are necessary to evaluate their efficacy in reducing fracture risks in larger thalassemic populations.