Monthly Intramuscular Neridronate for the Treatment of Postmenopausal Osteoporosis: Results of a 6-Year Prospective Italian Study

Effect of neridronate in osteopenic patients after heart, liver or lung transplant: a multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Transplantation (Tx) is an effective therapeutic option in patients with end-stage organ failure and osteoporosis and related fractures are a recognized complication in these patients. Aim of this study was to evaluate the efficacy of neridronate in patients with reduced bone mass after Tx of the heart, liver or lung.

METHODS

In this multicenter randomized double-blind controlled trial (RCT), 22 patients were treated with neridronate (25 mg i.m./month) and 17 received placebo. All patients received daily oral calcium (500 mg) and vitamin D (400 IU). Dual-energy X-ray absorptiometry (DXA) was evaluated at 0, 6 and 12 months and markers of bone turnover at 0, 3, 6, 9 and 12 months.

RESULTS

Thirty-nine patients (11 heart Tx, 21 liver Tx, 7 lung Tx), aged 49.3±9.1 years, with a T-score <-2.0 SD at lumbar spine or femoral level were included. In neridronate-treated patients, a significant increase in lumbar bone mineral density (BMD) was observed after 12 months vs. placebo control (0.92±0.13 g/cm² vs. 0.84±0.08 g/cm²; P=0.005). Femur and hip BMD remained unchanged between groups. Total alkaline phosphatase, bone alkaline phosphatase and beta-cross-laps significantly decreased over the 12 months in neridronate-treated patients vs. placebo, respectively (107.4±74 U/L vs. 157.6±107.1 U/L, P=0.002; 5.7±3.3 µg/L vs. 11.7±4.3 µg/L, P<0.001 and 0.25±0.13 ng/mL vs. 0.73±0.57 ng/mL, P<0.001). No difference was observed between neridronate and placebo groups regarding safety profile.

CONCLUSIONS

This is the first RCT that demonstrates the efficacy of neridronate in increasing bone density and reducing bone turnover in organ Tx recipients with significant skeletal morbidity.

Long non‑coding RNA XIST inhibits osteoblast differentiation and promotes osteoporosis via Nrf2 hyperactivation by targeting CUL3

Osteoporosis (OP) is a common skeletal disorder characterized by a low bone mass and the deterioration of bone structure. Long non‑coding (lnc)RNA X inactive‑specific transcript (XIST) is highly expressed in the serum and monocytes of patients with OP. Thus, the purpose of the present study was to explore the mechanisms underlying the role of XIST in the progression of OP. To establish animal models of OP, female rats underwent a bilateral ovariectomy. The bone mineral density of individual rats was measured using dual‑energy X‑ray absorptiometry. The combination of XIST and cullin‑3 (CUL3) was analyzed using a dual‑luciferase reporter assay. Bone histopathological changes were assessed by hematoxylin and eosin staining. Alkaline phosphatase activity was examined by ALP staining. Finally, a series of functional experiments were performed to examine the effects of XIST on cellular behaviors. In the present study, XIST promoted OP and inhibited bone formation by regulating the expression levels of CUL3 and nuclear factor erythroid 2‑related factor 2 (Nrf2) in the rats with OP. Moreover, XIST directly targeted CUL3 and negatively regulated its expression. Of note, CUL3 downregulation reversed the effects of XIST silencing on cell viability, differentiation and mineralization, as well as the expression of Nrf2 and CUL3 in MC3T3‑E1 cells. Collectively, XIST was demonstrated to inhibit the differentiation of osteoblasts and promote OP by inhibiting the degradation of Nrf2 via targeting CUL3.