Combining canine mesenchymal stromal cells and hyaluronic acid for cartilage repair

Human umbilical cord (hUC)- or bone marrow (hBM)-derived mesenchymal stromal cells (MSCs) were evaluated as an allogeneic source of cells for cartilage repair. We aimed to determine if they could enhance healing of chondral defects with or without the recruitment of endogenous cells. hMSCs were applied into a focal joint surface injury in knees of adult mice expressing tdTomato fluorescent protein in cells descending from Gdf5-expressing embryonic joint interzone cells. Three experimental groups were used: (i) hUC-MSCs, (ii) hBM-MSCs and (iii) PBS (vehicle) without cells. Cartilage repair was assessed after 8 weeks and tdTomato-expressing cells were detected by immunostaining. Plasma levels of pro-inflammatory mediators and other markers were measured by electrochemiluminescence. Both hUC-MSC (n = 14, p = 0.009) and hBM-MSC (n = 13, p = 0.006) treatment groups had significantly improved cartilage repair compared to controls (n = 18). While hMSCs were not detectable in the repair tissue at 8 weeks post-implantation, increased endogenous Gdf5-lineage cells were detected in repair tissue of hUC-MSC-treated mice. This xenogeneic study indicates that hMSCs enhance intrinsic cartilage repair mechanisms in mice. Hence, hMSCs, particularly the more proliferative hUC-MSCs, could represent an attractive allogeneic cell population for treating patients with chondral defects and perhaps prevent the onset and progression of osteoarthritis.

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Continuous Low-Intensity Ultrasound Preserves Mitochondrial Potential, Inhibits NFκB Activation and Rescues Chondrogenesis of Mesenchymal Stromal Cells

10.21203/rs.3.rs-342462/v1 ◽

2021 ◽

Author(s):

Sarayu Bhogoju ◽

Shahid Khan ◽

Denzhi Wang ◽

Anuradha Subramanian

Keyword(s):

Mesenchymal Stromal Cells ◽

Cartilage Repair ◽

Stromal Cells ◽

Nuclear Translocation ◽

Feedback Mechanism ◽

Protective Agent ◽

Mitochondrial Potential ◽

Qrt Pcr ◽

Low Intensity ◽

Low Intensity Ultrasound

Abstract Objective: Dysregulation of the anabolic processes in a proinflammatory joint environment coupled with impeded chondrogenic differentiation of mesenchymal stromal cells (MSCs) led to inferior cartilage repair outcomes. The preponderance of proinflammatory cytokines activated nuclear factor kappa B (NFκB) and impeded the chondrogenesis of MSCs. Thus, strategies that minimize the deleterious effects of activated NFκB while promoting MSC chondrogenesis are of interest. The present study establishes the ability of continuous low-intensity ultrasound (cLIUS) to rescue MSC chondrogenesis impacted by a proinflammatory environment. Methods: Human bone marrow-derived MSCs were seeded in alginate:collagen hydrogels and cultured for 21-days in an ultrasound-assisted bioreactor 14 kPa (5.0 MHz, 2.5 Vpp; 4-applications/day) for 21 days in the presence of IL1β and evaluated by qRT-PCR (n=10), immunofluorescence (n=15), western blotting (WB) (n=6), and immunohistochemistry (n=3). The differential expression of markers associated with NFκB pathway under cLIUS were evaluated upon a single exposure of cLIUS and assayed by qRT-PCR (n=3), immunofluorescence (n=30-60), WB (n=6) and tetramethylrhodamine methyl ester assay (n=50) was used to assess the mitochondrial potential under IL1β and cLIUS treatment.Results: Chondroinductive potential of cLIUS was preserved as noted by the increased expression of SOX9 and deposition of collagen II. cLIUS extended its chondroprotective effects by stabilizing the NFκB complex in the cytoplasm via engaging the IκBα feedback mechanism, thus preventing its nuclear translocation. cLIUS acted as a mitochondrial protective agent by restoring the mitochondrial potential and the mitochondrial mRNA expression in a proinflammatory environment. Conclusion: Our results demonstrated the potential of cLIUS for cartilage repair and regeneration under proinflammatory conditions.

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