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Preprints

Infrapatellar Fat Pad-derived Mesenchymal Stem Cell-based Spheroids Enhance Their Therapeutic Efficacy to Reverse Synovitis and Fat Pad Fibrosis

Kouroupis D, Willman MA, Best TM, Kaplan LD, Correa D.
Preprint from
Research Square
21 October 2020
PPR
PPR228418
Abstract

Background:

To investigate the in vitro and in vivo anti-inflammatory/anti-fibrotic capacity of IFP-MSC manufactured as 3D spheroids. According to our hypothesis, IFP-MSC do not require prior cell priming to acquire a robust immunomodulatory phenotype in vitro in order to efficiently reverse synovitis and IFP fibrosis and secondarily delay articular cartilage damage in vivo.

Methods:

Human IFP-MSC immunophenotype, tri-potentiality, and transcriptional profiles were assessed in 3D settings. Multiplex secretomes were assessed in IFP-MSC spheroids [Crude (non-immunoselected), CD146+ or CD146- immunoselected cells] and compared with 2D cultures with and without prior inflammatory/fibrotic cell priming. Functionally, immunopotency limiting human PBMCs proliferation and effect on stimulated synoviocytes with inflammation and fibrotic cues. Finally, spheroids were tested in vivo in a rat model of acute synovitis/fat pad fibrosis.

Results:

Spheroids enhanced IFP-MSC phenotypic, transcriptional and secretory immunomodulatory profiles compared to 2D cultures. Further, CD146+ IFP-MSC spheroids showed enhanced secretory and transcriptional profiles, however, not reflected in a superior capacity to suppress activated PBMC suggesting 3D environment sufficient to induce an immunomodulatory phenotype. Crude IFP-MSC spheroids modulated the molecular response of synoviocytes previously exposed to inflammatory cues. Therapeutically, IFP-MSC spheroids retained Substance P degradation potential in vivo, while effectively induced resolution of inflammation/fibrosis of synovium and fat pad, halting the articular cartilage degradation in a rat model of progressive synovitis, fat pad fibrosis and osteoarthritis.

Conclusions:

3D spheroids confer IFP-MSC a reproducible and enhanced immunomodulatory effect in vitro and in vivo, circumventing the requirement of non-compliant cell priming or selection before administration, thus streamlining cell products manufacturing protocols.