Serum OPN levels could be used as a biomarker for the early diagnosis of osteoporosis in postmenopausal women.

Shikonin, a major ingredient in the Chinese traditional herb Lithospermum erythrorhixon, exhibits multiple biological functions including antimicrobial, anti-inflammatory, and antitumor effects. In this study, we delineated the molecular mechanisms of shikonin in the apoptosis of 143B osteosarcoma cells. Shikonin reduced the cell viability of 143B cells in a dose-and time-dependent manner. The IC 50 at 24 h and 48 h for 143B cells was 4.55 and 2.01 m mM, respectively. A significantly elicited hypodiploid cell population was found in cells treated with 2, 4, and 8 m mM shikonin for 24 h. Moreover, treatment with shikonin induced reactive oxygen species (ROS) generation, increased extracellular signal-regulated kinase (ERK) phosphorylation, decreased B-cell lymphoma-2 (Bcl2) expression, and was accompanied by poly(ADP-ribose) polymerase (PARP) cleavage. Pretreatment with the antioxidant agent N-acetyl cysteine (NAC) not only reversed shikonin-induced ROS generation but also significantly attenuated the cytotoxic effects of shikonin in 143B cells. Furthermore, NAC attenuated shikonin-induced ERK phosphorylation. Taken together, our results reveal that shikonin increased ROS generation and ERK activation, and reduced Bcl2, which consequently caused the cells to undergo apoptosis. Therefore, shikonin may be a promising chemotherapeutic agent for osteosarcoma treatment.

Background: Advanced glycation end-products (AGEs) can accumulate in organs and tissues during ageing and diabetes. Increased levels of AGEs are found in the bone tissue of patients with osteoporosis. The purpose of this study was to evaluate circulating AGEs in patients with osteoporosis.Methods: We evaluated plasma AGEs, osteoporosis-related biomarkers, and bone mass in 82 menopausal women with osteoporosis or osteopenia, 16 young women with osteopenia, and 43 healthy women without osteoporosis or osteopenia.Results: Higher levels of serum AGEs were found in the osteoporosis or osteopenia group compared to healthy women (P < 0.0001). A negative correlation was observed between serum AGEs and lumbar spine bone density (BMD of lumbar spine, r = -0.249, P = 0.028; T-score of lumbar spine, r = -0.261, P = 0.021). Women with a increased level of serum AGEs (> 8.12 U/mL) had a 5.34-fold risk of osteopenia regarding lumbar spine T-score and a 3.31-fold risk of osteopenia regarding the hip T-score.Conclusion: Serum AGEs could be used to monitor the severity and progression of osteoporosis. An increased serum level of AGEs was associated with impaired bone formation and was a risk factor for the development of osteoporosis. Targeting AGEs may represent a novel therapeutic approach for primary or secondary osteoporosis.