The Expression Of MicroRNAs From Patients With Osteoporotic Vertebral Compression Fractures

PURPOSE: Osteoporosis is one of the most common senile diseases,often leading to low back pain,compression fractures,etc.,but the current clinical diagnosis is bone mineral density(BMD)measured by dual energy X-ray absorptiometry(DEXA).When BMD loses 2.5 standard deviations(SD),the patients were diagnosed as osteopororis,which have several limitations.First,the diagnosis is usually at middle or late stage,instead of early stage for the patients based on the result from DEXA.Second,BMD from DEXA can not provide information the bone microstructure and bone strength,which is the key factors contributing to the fractures in osteoporotic patients.The aim of the study,therefore,is to explore the expression profiles of microRNA in osteoporotic patients with or without vertebral fractures.METHODS:1.Screening and comparison of miRNAs and age-matched healthy human miRNAs in osteoporosis patients: The peripheral blood of patients was taken for miRNAs mapping,and the bone pine group and the normal group were compared.When the P value of miRNAs is less than 0.05 and the doubling number is less than0.5 and greater than 2,it is considered to be a significant change in miRNAs.2.Screening and comparison of miRNAs and age-matched healthy human miRNAs in osteoporotic vertebral fractures: Peripheral blood of patients with vertebral fractures was analyzed for miRNAs expression,and compared with the normal group.When the P value of miRNAs is less than 0.05 and the doubling number is less than 0.5 and greater than 2,it is considered to be a significant change in miRNAs.3.In vitro PCR validation of specific miRNAs: miRNAs were used to select potential miRNAs that met the criteria,and real-time quantitative PCR was used to validate miRNAs from patients with osteoporosis and osteoporotic vertebral fractures.RESULTS:1.Differentially expressed miRNAs in the plasma of osteoporotic patients:We initially profiled the miRNA spectra via the Human Serum & Plasma miRNA PCR Arrays from a pool of six samples from osteoporotic patients with vertebral fractures,a pool of six samples from osteoporotic patients without vertebralfractures and another pool of six samples from non-osteoporotic patients to identify the discrepant plasma miRNAs.A total of 384 different miRNAs could be captured using the mentioned array.Differentially expressed miRNAs were selected by volcano plot filtering(fold change ?2.0 and P-value ?0.05).There were 118 upregulated miRNAs and 266 down-regulated miRNAs as the fold numbers presented.Multiple miRNAs have significantly different expression level between osteoporotic group and non-osteoporotic control group.Remarkably,a distinct miRNA profile was exhibited between osteoporotic group with vertebral fracture and osteoporotic group without vertebral fracture.Then we performed hierarchical clustering of these miRNAs.We found these miRNAs clearly discriminated osteoporosis from healthy control.These results suggest that the profiling of miRNAs in plasma can be utilized to discriminate osteoporosis.2.miR-19 b differential expression verification analysis:To assess the potential of using miRNAs as biomarkers in osteoporosis,we chose miR-19 b with detectable circulating abundance for validation experiments.Here,we used q-PCR on an independent validation sample set,which consisted of serum samples from a pool of 24 osteoporotic patients with vertebral fractures,a pool of 24 osteoporotic patients without vertebral fracture and another pool of 24 samples from health control.The results showed that miR-19 b could significantly distinguish osteoporosis samples from samples of nonosteoporotic controls.CONCLUSIONS:1.In this study,a comparative study of serum miRNAs expression profiles in osteoporosis group,osteoporotic vertebral fracture group and the age-matched healthy group showed that there was significant difference between osteoporosis group and healthy age group.There were no significant expressions of miRNAs between the osteoporotic vertebral fracture group and the osteoporotic vertebral fracture group.2.In this study,we found that miR-19 b is significantly down-regulated in osteoporotic patients compared with healthy individuals of the same age,suggesting that miR-19 b may play an important role in the pathogenesis of osteoporosis.Theunderlying mechanisms for the effect of miR-19 b on bone metabolism remains unknown and needs to be further explored.