Autophagy in osteoporosis: Relation to oxidative stress.

Impaired autophagy and oxidative stress are implicated in the development of many diseases. This study aimed to investigate the involvement of autophagy represented by autophagy-related gene 7 (Atg7) and oxidative stress represented by superoxide dismutase 2 (SOD2) gene expression and enzyme activity in the pathogenesis of osteoporosis. Atg7 and SOD2 gene relative expression were evaluated by SYBR green quantitative real-time-polymerase chain reaction in the osteoporotic group (n = 26) versus the osteoporosis free group (n = 14). SOD2 enzyme activity was evaluated by colorimetric method in both study groups. Both Atg7 and SOD2 relative expression showed highly significant decrease (P < 0.01) between both groups. However, SOD2 enzyme activity showed no significant difference between the two groups. There was a significant direct correlation between Atg7 and SOD2 gene expression in both study groups. Atg7 relative expression showed significant ( P < 0.01) direct correlation with vitamin D serum levels and body mass index in osteoporotic group. In conclusion, both genes are involved in the pathogenesis of osteoporosis and this could be amenable to future therapeutic intervention.

Insight into the possible role of miR-214 in primary osteoporosis via osterix.

Osteoporosis is a bone disease characterized by chronic pain and recurrent fractures. Osterix is a transcription factor regulating bone formation. miR-214 was found to have a role in skeletogenesis. Our goal was to investigate the possible role of miR-214 in primary osteoporosis through osterix. Their expression was determined in bone samples obtained from primary osteoporotic patients (n = 26) and age- and sex-matched controls (n = 14). Additionally, their expression was correlated to the laboratory and clinical parameters of the study participants. Differential expression of osterix and miR-214 was detected in the osteoporotic group compared to controls. While miR-214 was significantly higher, osterix was significantly lower. In primary osteoporotic patients, relative quantification value of osterix was positively correlated with sex, body mass index, and ionized calcium and negatively correlated with miR-214 and C-reactive protein. Thus, the role of miR-214 in primary osteoporosis could be through inhibiting osterix expression in bones and therefore both miR-214 and osterix could be targets for future therapeutic intervention.

Expression of nucleostemin gene in primary osteoarthritis.

INTRODUCTION: The identification of genes associated with osteoarthritis can help reveal underlying biological mechanisms that may lead to development of new therapeutic targets or biomarkers for early detection and risk stratification. Nucleostemin (GNL3) is a nucleolar GTPase initially identified in the nucleolus of rat neural stem cells. The current study was conducted to determine the expression of nucleostemin gene in the synovium and synovial fluid of patients with primary osteoarthritis and to correlate its expression to the different clinicopathological factors of the disease. PATIENTS AND METHODS: It included 31 patients with primary knee osteoarthritis and 25 osteoarthritis free patients served as a control group. Synovial tissue and synovial fluid samples were obtained directly from each patient for real time PCR of GNL3. RESULTS: Relative expression of GNL3 in synovial tissue and fluid samples was significantly higher in the osteoarthritic group as compared to the non-osteoarthritic group. GNL3 relative expression in both samples showed a significant difference among different BMI categories and among different radiographic grades of osteoarthritis. A high significant correlation was found between GNL3 relative expression levels in synovial tissue samples and those of synovial fluid samples with concordance of 85.7%. CONCLUSION: Nucleostemin could serve as a powerful prognostic marker for clinical use in osteoarthritis and its usefulness needs to be standardized and validated in a large-scale prospective multicentric study.