Identification of mirnas in patients with steroid-induced femoral head avascular necrosis

Avascular necrosis (AVN) is a progressive bone disorder characterized by cell death, structural collapse, and eventual functional impairment of the affected area. Notably, AVN can develop in various bones, including the upper extremities, knees, shoulders, and ankles. It can even affect multiple bones at different times. Both traumatic and atraumatic factors contribute to AVN formation, with steroid use being a prominent atraumatic contributor. Steroid-induced AVN (SANFH) presents a particularly complex challenge due to its multifaceted effects on bone physiology. These effects encompass osteoblast differentiation, osteoblast and osteoclast apoptosis, lipid metabolism, coagulation pathways, and calcium homeostasis. Steroid hormones are essential biomolecules synthesized from cholesterol through a process called steroidogenesis. While corticosteroids are invaluable in treating various diseases, they are known to disrupt bone homeostasis by reducing the production of osteoblasts and osteoclasts while simultaneously prolonging osteoclast lifespan and promoting osteoblast apoptosis. MicroRNAs (miRNAs) are short, non-coding RNAs that act as powerful gene regulators across diverse biological processes in animals and plants. They achieve this by interacting with a vast array of target genes. Notably, miRNAs are highly conserved across species, and their altered expression levels serve as diagnostic tools for various diseases. Recent research suggests that miRNA expression levels are dysregulated in SANFH, particularly those involved in osteoblast differentiation. This observation highlights their potential as biomarkers for clinical practice. In the present study, we employed in silico methods to identify miRNA sequences associated with SANFH-related genes RIPK1 and MAPK. We then evaluated the relationship between these sequences and selected hsa-miR-6891 for the RIPK1 gene and hsa-miR-5699 for the MAPK gene for further analysis using RT-qPCR. Peripheral blood samples were collected from 15 patients diagnosed with SANFH and 15 patients without a diagnosis of SANFH who applied to Amasya Sabuncuoğlu Şerefeddin Training and Research Hospital, Department of Orthopedics and Traumatology, and total RNA was isolated for miRNA analysis. Our RT-qPCR results revealed a significant downregulation of hsa-miR-6891 expression in the blood of individuals with SANFH. While hsa-miR-5699 levels exhibited an upward trend in the SANFH group, this increase did not reach statistical significance. Based on these findings, we hypothesize that hsa-miR-6891 and hsa-miR-5699 may be associated with SANFH and hold promise as potential biomarkers for disease diagnosis and prognosis.