Adipose tissue as a living drug: Stromal vascular fraction and adipose tissue-derived stem cells in regenerative medicine

Table 4 Comparison of stromal vascular fraction and adipose-derived stem cells

Features	SVF	ASCs
Definition	A heterogeneous cell mixture obtained directly from adipose tissue enzymatically or mechanically, comprising diverse stromal and immune cell populations	A relatively homogeneous mesenchymal stromal cell population derived from adherent culture and expansion of SVF
Composition	Fibroblasts, endothelial cells, pericytes, smooth muscle cells, blood-derived cells, immune cells (T-cells, macrophages), and progenitor and stem cells (ASCs)	Enriched in plastic-adherent multipotent MSCs with a fibroblast-like morphology, showing minimal hematopoietic contamination after passaging
Heterogeneity	Highly heterogeneous	Relatively homogeneous
Markers	CD34, CD45, CD31	CD73, CD90, CD105
Isolation methods	Single-step procedure following collagenase digestion or mechanical dissociation, without the need for culture or expansion	Requires isolation from SVF followed by culture expansion over many days to weeks to enrich the adherent cell population
Mechanism of action	Vascular/immune cells drive angiogenesis, immunomodulation, and tissue support, while ASCs contribute differentiation	Combination of direct differentiation and strong paracrine effects (secretion of VEGF, HGF, IGF-1, extracellular vesicles)
Differentiation potential	Variable potential (due to cellular heterogeneity)	Multilineage potential (adipogenic, osteogenic, chondrogenic)
Timeframe for use	Immediate use application (cells can be reinjected within the same procedure)	Not immediate use (requires laboratory processing and expansion)
Yield per gram of AT	Yields approximately 500000 to 2000000 nucleated cells per gram of fat but only 1%-10% are progenitors/stem cells[50]	Yields approximately 5000-200000 ASCs per gram of fat after culture expansion depending on passages and technique[51]
Scalability	Constrained by harvest volume and regulatory restrictions, as large-scale expansion is not feasible with same-day isolations	Easily scalable through in vitro expansion, allowing production of large cell doses from relatively small adipose samples
Clinical readiness	Used in autologous cell therapies (especially for cosmetic and orthopedic applications) as regulatory approval easier since it regarded as minimally manipulated	Ongoing clinical trials in diverse fields (cardiovascular, musculoskeletal, inflammatory) as this requires GMP culture facilities
Key advantages	Quick, cost-effective, and maintains cellular diversity	More defined, reproducible, and expandable population
Current limitations	Batch variability, lower predictability of outcomes and regulatory debate on enzymatic methods	Time-consuming, cost-intensive, requires GMP conditions for clinical use

SVF: Stromal vascular fraction; ASCs: Adipose-derived stem cells; MSC: Mesenchymal stem cell; VEGF: Vascular endothelial growth factor; HGF: Hepatocyte growth factor; IGF-1: Insulin-like growth factor 1; GMP: Good manufacturing practice.