Thawed Cryopreserved Synovial Mesenchymal Stem Cells Show Comparable Effects to Cultured Cells in the Inhibition of Osteoarthritis Progression in Rats

Abstract

Background Intra-articular injections of mesenchymal stem cells (MSCs) can inhibit the progression of osteoarthritis (OA) in animal studies. Previous reports have used cultured MSCs, but the ability to use thawed cryopreserved MSC stocks would be highly advantageous. Our purpose was to elucidate whether thawed cryopreserved MSCs show comparable inhibitory effects on OA progression in rats to those obtained with cultured MSCs. Methods Cultured rat synovial MSCs or thawed MSCs were compared for in vitro viability and properties. The activity of synovial MSCs derived from rats expressing luciferase was compared by the luminescence intensity both in vitro and in vivo. The inhibitory effect of cultured MSCs on OA progression was evaluated by injecting PBS and cultured MSCs into the right and left knees, respectively, of the same individual meniscectomized rats. A similar test evaluated cryopreservation fluid (95% FBS with 5% DMSO; termed the 95% FBS group) versus thawed MSCs. Cartilage degeneration was assessed at 4 and 8 weeks using gross finding and histological scores. The results were used to set the primary outcome and sample size. Cultured MSCs were then injected into one knee and thawed MSCs into the contralateral knee of the same individual to compare their effects.Results Cultured MSCs and MSCs thawed after cryopreservation in 95% FBS with 5% DMSO had comparable in vitro viability, colony formation, and chondrogenic potential. The luminescence intensity was comparable between the two MSC preparations. In the rat OA model, the gross findings and histological scores for tibial cartilage did not differ at four weeks but were significantly lower in the cultured MSC group than in the PBS group and significantly lower in the thawed MSC group than in the 95% FBS group at eight weeks. These results established the tibial cartilage histological score at eight weeks as the primary outcome and a sample size of nine for comparing cultured versus thawed MSCs. The tibial cartilage histological scores did not differ significantly at eight weeks after injection of cultured and thawed MSCs into the opposite knees of the same individuals.ConclusionsThawed MSCs showed comparable inhibitory effects on OA progression to cultured MSCs.

Cryopreservation does not change the performance and characteristics of allogenic mesenchymal stem cells highly over-expressing a cytoplasmic therapeutic transgene for cancer treatment

“…The successful development of 'off-the-shelf ' GDEPT is dependent on cells retaining their therapeutic functions post freeze-thaw. Majority of the studies examined impact of cryopreservation on functionality of MSC such as their immunomodulatory [46,51], anti-inflammatory properties [17,58] and regenerative properties [59,60]. In contrast to the defined pharmacokinetics of single agent, unmodified MSC therapeutics demonstrate conditional, complex and multifactorial paracrine effect in vitro and in vivo [55][56][57].…”