A Comparative Analysis of the Infrapatellar Fat Pad and Subcutaneous Adipose Tissue as Providers of Mesenchymal Stem Cells with Chondrogenic Potential: Quantitative Assessment through Immunohistochemical Methods

Abstract

The limited regenerative capacity of articular cartilage necessitates effective treatment methods for its repair. Infrapatellar fat pad (IPFP)-derived adipose stem cells (ASCs) demonstrate superior chondrogenic potential compared to subcutaneous adipose tissue (SCAT)-derived ASCs, making IPFP a promising source for cartilage regeneration. This study aimed to compare the quantitative expression of chondrogenic markers in mesenchymal stem cells (MSCs) derived from the IPFP and SCAT. Biopsy samples were collected from 25 patients undergoing knee osteoarthritis treatment. Histological and immunohistochemical analyses were performed on IPFP and SCAT samples, focusing on CD44, CD166, and SOX9 markers. The IPFP samples exhibited significantly higher relative numbers of CD44+ (13.28%), CD166+ (10.34%), and SOX9+ (7.30%) cells compared to SCAT samples, where values were 1.40%, 1.10%, and 0.90%, respectively. The differences were statistically significant (p < 0.05). IPFP-ASCs showed enhanced stability in marker expression, suggesting their specialization for chondrogenic differentiation. IPFP is a superior source of MSCs for cartilage repair, with a significantly higher presence of CD44+, CD166+, and SOX9+ cells compared to SCAT. These findings highlight the potential of IPFP-derived ASCs in regenerative cartilage therapy and underscore the importance of their anatomical proximity to cartilage tissue.