Abstract
Introduction
The most frequent diagnosis in young adults undergoing total hip arthroplasty (THA) is osteonecrosis of the femoral head (ONFH), an evolving and disabling condition with an increasing prevalence worldwide. Treatment of ONFH remains a challenge mainly because of a lack of understanding of the disease's pathophysiological basis. This study investigated the biological processes that could be affected by ONFH by comparing the microstructure, histological characteristics and transcriptomic profile of trabecular bone from the femoral head (FH) and the intertrochanteric region (IT) of patients suffering from this condition.
Method
A total of 18 patients with idiopathic ONFH undergoing THA in our institution were included. Trabecular bone explants were taken intraoperatively from the FH and the IT of patients. Bone microstructure was examined by micro-computed tomography (micro-CT). After bone sectioning, histological features were studied by hematoxylin and eosin staining. Differential gene expression was investigated using a microarray platform.
Result
Micro-CT imaging showed higher trabecular separation and lower trabecular thickness and bone volume in trabecular bone from the FH than from the IT. Histological staining revealed that the number of osteoblasts on the bone surface and the percentage of empty lacunae were higher in trabecular bone from the FH. Transcriptome analysis identified a differential signature in trabecular bone from the FH compared to the IT. The gene ontology analyses of the genes overexpressed in trabecular bone from the FH revealed a range of enriched biological processes related to cell division and immune response. In contrast, most downregulated transcripts were involved in bone formation.
Conclusion
This study identified changes in the microarchitecture, histological features and transcriptomic signature of trabecular bone from the FH of patients with idiopathic ONFH, which might underlie the pathophysiology of this condition. This work was supported by PI22/00939 grant from ISCIII-FEDER-MICINN-AES and Luis Alvarez grant from IdiPAZ.
