Stromal Vascular Fraction for Osteoarthritis of the Knee Regenerative Engineering

Abstract

Purpose: The knee joint is prone to osteoarthritis (OA) due to its anatomical position, and several reports have implicated the imbalance between catabolic and anabolic processes within the joint as the main culprit, thus leading to investigations towards attenuation of these inflammatory signals for OA treatment. In this review, we have explored clinical evidence supporting the use of stromal vascular fraction (SVF), known for its anti-inflammatory characteristics for the treatment of OA.

Methods: Searches were made on PubMed, PMC, and Google Scholar with the keywords "adipose fraction knee regeneration, and stromal vascular fraction knee regeneration, and limiting searches within 2017-2020.

Results: Frequently found interventions include cultured adipose-derived stem cells (ADSCs), SVF, and the micronized/microfragmented adipose tissue-stromal vascular fraction (MAT-SVF). Clinical data reported that joints treated with SVF provided a better quality of life to patients. Currently, MAT-SVF obtained and administered at the point of care is approved by the Food and Drug Administration (FDA), but more studies including manufacturing validation, safety, and proof of pharmacological activity are needed for SVF. The mechanism of action of MAT-SVF is also not fully understood. However, the current hypothesis indicates a direct adherence and integration with the degenerative host tissue, and/or trophic effects resulting from the secretome of constituent cells.

Conclusion: Our review of the literature on stromal vascular fraction and related therapy use has found evidence of efficacy in results. More research and clinical patient follow-up are needed to determine the proper place of these therapies in the treatment of osteoarthritis of the knee.

Lay summary: Reports have implicated the increased inflammatory proteins within the joints as the main cause of osteoarthritis (OA). This has attracted interest towards addressing these inflammatory proteins as a way of treatment for OA. The concentrated cell-packed portion of the adipose product stromal vascular fraction (SVF) from liposuction or other methods possesses anti-inflammatory effects and has been acclaimed to heal OA. Thus, we searched for clinical evidence supporting their use, for OA treatment through examining the literature. Data from various hospitals support that joints treated with SVF provided a better quality of life to patients. Currently, there is at least one version of these products that are obtained and given back to patients during a single clinic visit, approved by the FDA.

Keywords: Adipose tissue; Knee regeneration; Osteoarthritis; Stromal vascular fraction.

Fig. 1

A Different cells that make up SVF and MAT-SVF. B Cells, frequency of occurrence, and associated markers of SVF and MAT-SVF

Fig. 2

Devices used for SVF and SVF-MAT isolation. a GID-SVF1. b Puregraft 250. c Stem.pras. d Reference method. Adapted from Jonathan Rodriguez et al., 2017 [35]

Fig. 3

A X-ray was taken in a weighted postero-anterior view of the knee at 45° flexion (Rosenberg’s view), showing a slight and moderate medial joint space narrowing in the right and left knee, respectively (KL grades II, III). B Preoperative arthroscopic findings in the right and left medial femoral condyles show 2.5 × 1.5 cm cartilage defect in the right knee (a), and 3 × 1.5 cm cartilage defect in the left knee (b). C Second-look arthroscopic findings in the right and left medial femoral condyles 6 months post-operation revealed that the cartilage defect area was covered by regenerated cartilage. ((a) right), ((b) left). Adapted from Yuma Onoi et al., 2019 [8]

Fig. 4

A Schematic diagram illustrating the capacity for MSC and pericyte differentiation into separate lineages (gray and pink arrows) and self-renewal (red arrows). The unique and shared markers of both cell types are shown. Adapted from Suet-Ping Wong et al., 2015, Ref (#39). B Paracrine effects of MSCs. The secretion of a broad range of bioactive molecules is believed to be the main mechanism by which MSCs achieve their therapeutic effect and it can be divided into six main categories: immunomodulation, anti-apoptosis, angiogenesis, support of the growth and differentiation of local stem and progenitor cells, anti-scarring, and chemo-attraction. Although the number of molecules known to mediate the paracrine action of MSCs increases every day. Adapted from Meirelles et al., 2009, [38]