Clarifying the critical differences between the enzymatic stromal vascular fraction and the mechanically derived stromal vascular tissue or nanofat for spinal cord injury applications

Abstract

This letter aims to address the increasing confusion surrounding the concepts and terminology of enzymatically derived stromal vascular fraction (eSVF) and mechanically processed adipose tissue, which is often referred to as stromal vascular tissue (mSVT) or nanofat. Although these products are often presented as equivalent, they differ fundamentally in their biological composition, processing methods and regulatory classification. Enzymatic digestion yields a homogeneous, adipocyte-free cellular suspension, whereas mechanical processing preserves adipocytes, extracellular matrix fragments and tissue architecture. In the context of spinal cord injury, these differences give rise to biologically plausible concerns and procedural constraints, particularly with regard to intramedullary delivery. This work highlights the importance of precise terminology, transparent reporting of methods, and careful regulatory alignment to ensure the safe and scientifically sound translation of clinical applications.

Keywords: Adipose-derived cells; Clinical translation; Collagenase; Enzymatic digestion; Mechanical processing; Nanofat; Regenerative medicine; Regulation; Spinal cord injury (SCI); Stromal vascular fraction (SVF); Stromal vascular tissue (SVT).