Microfluidic ExoBONE Assay for Predicting Bone Mineral Density Improvement in Primary Hyperparathyroidism

Abstract

Primary hyperparathyroidism (PHPT) is an endocrine disorder characterized by elevated serum calcium and parathyroid hormone levels, frequently leading to bone loss and increased fracture risk. Although para-thyroidectomy is the definitive treatment, only a subset of patients exhibits significant bone mineral density (BMD) improvement after surgery. To address the unmet need for predictive biomarkers for BMD improvement, we developed the ExoBONE assay, a microfluidic-based diagnostic platform that integrates selective isolation and molecular analysis of extracellular vesicles (EVs). Using a horseshoe-shaped micro-mixer chip, we efficiently isolated flotillin-1-positive EVs from the plasma of PHPT patients. We then profiled EV-associated microRNAs and identified hsa-miR-125b-5p and hsa-miR-19b-3p as predictive markers for postoperative BMD recovery at the femoral neck and total hip, respectively. Notably, hsa-miR-125b-5p retained its predictive performance even after adjusting for key clinical covariates, such as age, sex, and baseline PTH and P1NP levels, supporting its robustness as a functional EV cargo marker. The ExoBONE assay enables minimally invasive and target-specific prediction of skeletal response to surgery, offering a clinically translatable strategy for personalized bone health monitoring. This study highlights the potential of microfluidic EV isolation and integrated molecular profiling in metabolic bone disease and postoperative outcome assessment.