Infrapatellar Fat Pad Stem Cells Responsiveness to Microenvironment in Osteoarthritis: From Morphology to Function

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Cell Biology

Background:

• Infrapatellar fat pad (IFP) stem cells are explored for cartilage regeneration in osteoarthritis (OA).
• OA's inflammatory environment may alter stem cell properties and function.

Purpose of the Study:

• To characterize the structural and functional properties of stem cells from osteoarthritic IFP (OA-IFP).
• To investigate the impact of the OA pathological environment on these stem cells.

Main Methods:

• Isolation and characterization of OA-IFP stem cells from nine OA patients undergoing knee arthroplasty.
• Analysis included morphology, stemness markers, metabolic profile, and multi-differentiation potential via electron microscopy, flow cytometry, gene expression, and cytochemistry.

Main Results:

• OA-IFP stem cells displayed spindle morphology, self-renewal, and responsiveness to stimuli.
• High stemness markers (STAT3, NOTCH1, c-Myc, OCT-4, KLF4, NANOG) and specific immunophenotype (CD73+, CD39+, CD90+, CD105+, CD44-/+, CD45-).
• Inflammation-induced reprogramming suggested by HLA-DR, CD34, Fas, FasL expression; potential mechanical stress response (COL1A1); limited ability to counteract inflammation (low CD38/NADase).

Conclusions:

• OA-IFP stem cells are primed by the pathological OA environment.
• These cells may offer incomplete protection against OA inflammation and mechanical stress.