ABSTRACT
OBJECTIVE: The goal of this study was to characterize the microRNA (miRNA) expression signatures in patients with Primary hyperparathyroidism (PHPT) and identify miRNA biomarkers of bone homeostasis. BACKGROUND: PHPT is associated with increased bone turnover and decreased bone mass. miRNA are markers of bone remodeling. METHODS: We performed a prospective case-control study of postmenopausal females with PHPT and control subjects matched for race, age, and bone mineral density (BMD). We collected clinical and biochemical data, assessed BMD by dual-energy x-ray absorptiometry, and measured 27 serum miRNAs related to bone remodeling. We used linear regression to assess the correlation between miRNA levels, conventional biochemical markers, and BMD. RESULTS: A total of 135 subjects were evaluated, including 49 with PHPT (discovery group), 47 control patients without PHPT, and an independent validation cohort of 39 PHPT patients. Of 27 miRNAs evaluated, 9 (miR-335-5p, miR-130b-3p, miR-125b-5p, miR-23a-3p, miR-152-3p, miR-582-5p, miR-144-5p, miR-320a, and miR-19b-3p) were differentially expressed in PHPT compared with matched control subjects. All 9 differentially expressed miRNAs significantly correlated with levels of serum parathyroid hormone (PTH), and 8 of the 9 correlated with calcium levels. No differentially expressed miRNAs were consistently correlated with markers of BMD. Subjects with PHPT segregate from controls based on the signature of these 9 miRNAs on principle component analysis. CONCLUSIONS: These data suggest that PHPT is characterized by a unique miRNA signature that is distinct from postmenopausal and idiopathic osteoporosis. Levels of specific miRNAs significantly correlate with PTH, suggesting that bone remodeling in PHPT may be mediated in part by PTH-induced changes in miRNA.