Micro-fragmentation is a valid alternative to cell expansion and enzymatic digestion of adipose tissue for the treatment of knee osteoarthritis: a comparative preclinical study

Abstract

Purpose The aim of this study was to compare three procedures to exploit adipose-derived cells for the treatment of osteoarthritis (OA) in a preclinical model, to understand their therapeutic potential and identify the most suitable approach for the clinical application. Methods Biological samples from adipose tissue, processed by mechanical micro-fragmentation (MF), enzymatic digestion (SVF) or cell expansion (ADSCs), were irst characterized in vitro and then used in vivo in a surgically induced OA rabbit model: Group 1-control group (untreated 12 knees/saline 12 knees), Group 2-MF (24 knees), Group 3-SVF (24 knees), Group 4-ADSCs (24 knees). Macroscopic, histological, histomorphometric, immunohistochemical and blood and synovial luid analyses were evaluated at 2 and 4 months from the treatments. Results Samples obtained by the three procedures yielded 85-95% of viable cells. In vivo assessments showed no signiicant side efects or inlammatory responses after the injection. The macroscopic Hanashi score did not show signiicant diferences among treated groups and controls. The histopathological evaluation of synovial tissues showed lower signs of synovitis for MF, although the semiquantitative analysis (Krenn score) did not reach statistical signiicance. Instead, MF showed the best results both in terms of qualitative and semi-quantitative evaluations of articular cartilage, with a more uniform staining, a smoother surface and a signiicantly better Laverty score (p = 0.004). Conclusion MF, SVF, and expanded ADSCs did not elicit signiicant local or systemic adverse reactions in this preclinical OA model. Among the diferent methods used to exploit the adipose tissue potential, MF showed the most promising indings in particular in terms of protection of the articular surface from the joint degenerative OA processes. Level of evidence Preclinical animal study.

Microfragmented adipose tissue is associated with improved ex vivo performance linked to HOXB7 and b-FGF expression

“…The current study clarified some aspects of AT behaviour ex vivo and demonstrated that better preserved AT features are obtained using microfragmentation rather than centrifugation during ex vivo manipulation. A positive outcome in osteoarthritis treatment has been reported [ 10 , 11 , 38 ] MF-AT had surprisingly higher HOXB7 and bFGF expression in a pathologic SF environment, suggesting that these features are possible players in the beneficial impact on joint homeostasis. To investigate which AT processing method better preserves AT histology and performance and promotes regenerative mechanisms, two different methods (MF vs. C) were compared.…”

“…Several evidences report a significant positive clinical outcome such us in plastic surgery in the treatment of ulcers, burns, scars, soft tissue augmentation [ 5 , 7 – 9 ]. The application of AT-MSC was not confined to plastic surgery but was also extended to cardiac, rheumatoid, gastro-intestinal and musco-skeletal fields, etc [ 10 – 12 ]. For this reason, different enzymatic and mechanical procedures have been established for processing AT to isolate cells that can be locally implanted [ 13 , 14 ].…”

Autologous Microfragmented Adipose Tissue for the Treatment of Knee Osteoarthritis: Real-World Data at Two Years Follow-Up

“…Indeed, MFAT was demonstrated to support cell viability, proliferation, and extracellular matrix deposition, as well as to reduce the markers of inflammation and matrix degradation in several cell types, including cartilage cells and synoviocytes [ 24 ]. In vivo, MFAT was able to improve cartilage defects repair [ 25 ], and to exert a chondro-protective action in a rabbit model of OA [ 26 ]. The mechanism of these actions depends on paracrine effectors, such as soluble molecules or extracellular vesicles that are released by the cells contained in MFAT, and that have been identified as mediators with anti-inflammatory and pro-regenerative properties [ 27 , 28 ].…”

A Roadmap of In Vitro Models in Osteoarthritis: A Focus on Their Biological Relevance in Regenerative Medicine

“…The feasibility of using MSCs from bone marrow and other tissue sites, based on their ability to influence and regulate different stages of tissue repair, is a great challenge among clinicians [ 51 , 52 ]. MSCs can be present as expanded cells, following tissue collection and isolation, or as a heterogeneous population after concentration processes with different devices [ 53 , 54 , 55 , 56 ]. Expanded MSCs and concentrated progenitors undergo different regulatory compliance, as the first approach foresees cell manipulation in GMP facilities and two-step procedures, whereas the second one requires minimal manipulation and occurs through a one-step procedure directly in the operating room [ 57 ].…”