Cryopreservation is the only established method to provide long-term storage and fast availability of cellular product for therapeutic applications. The overwhelming majority of cryopreservation media contain toxic concentrations of dimethyl sulfoxide (DMSO) limiting the possibility for the direct administration of cryopreserved cells to the patients. Here, we propose a novel approach for nontoxic xeno-free cryopreservation of human multipotent mesenchymal stromal cells (MSCs) aimed at ensuring high viability, ready-to-use availability, and localized delivery of the cell-based graft into damaged tissues. For MSC cryopreservation, we applied sucrose pretreatment procedure and xeno-free cryoprotective medium containing human platelet-poor blood plasma (PPP), sucrose, and nontoxic concentration of DMSO. Using the combination of PPP, 0.2 M sucrose, and 1% DMSO, the recovery rate of cryopreserved MSCs reached 73% of the values obtained for noncryopreserved cells. Moreover, the presence of PPP in the cryoprotective medium provided the possibility to create a ready-to-use 3D hydrogel for the localized delivery and additional support of MSCs in vivo. In a proof-of-concept study, we assessed the regenerative capacity of cryopreserved MSCs in a full-thickness wound model in mice. The positive impact of MSCs within 3D gel on wound healing rates was confirmed by morphometric and histological examinations. Our results demonstrate the possibility to apply cryopreserved cells immediately after thawing using a cryoprotective medium as the vehicle solution.

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Hepatocyte transplantation is a promising method for supporting hepatic function in a broad spectrum of liver diseases. The aim of this work was to test the efficacy of human fetal liver cells to support the chronic failing liver in an experimental model of carbon tetrachloride (CCl4)-induced cirrhosis in rats. Liver cirrhosis was induced by intraperitoneal administration of CCl4 at a dose of 0.2 ml (50% v/v solution)/100 g body weight, twice a week for 3 months in rats. Ten days after stopping CCl4 administration (experimental day 0), rats received intrasplenic injection of cryopreserved fetal liver cells (FLC, 1 × 107 cells in 0.3 ml medium). As a cirrhotic control group, CCl4-induced cirrhotic rats were used with intrasplenic injection of an equal volume of medium alone. Animals were sacrificed on experimental day 15. Human fetal liver cell transplantation almost completely prevented the death of cirrhotic animals during the 2 weeks after treatment, while high ongoing mortality was seen in the cirrhotic control group. Cell transplantation into the spleen normalized total bilirubin and TBARSs levels and increased albumin levels in blood serum, as well as restoring mitochondrial function and liver detoxification function (assessed by cytochrome P450 contents and activity) compared with the activities seen in the cirrhosis control group. In parallel with this restoration of biochemical and functional liver indices, morphological patterns of liver recovery or regeneration after liver cell transplantation were demonstrated in day 15 samples by light microscopy. These were absent in the group that had received only medium alone.

The aim of study was to comparatively evaluate the morphological and functional properties of cryopreserved multipotent mesenchymal stromal cells (MMSCs) from bone marrow, fat and tendon.Materials and methods. MMSC cultures obtained from rat bone marrow, fat and tendon. The cells was cryopreserved under protection of 10 % DMSO and 20% FBS with cooling rate of 1 deg/min down to -80°C followed by plunging into liquid nitrogen. In the studied cultures the membrane integrity, immunophenotype, ability to colony formation, proliferative characteristics (MTT-test), directed differentiation and type I collagen synthesis were evaluated.Results. Investigated cryopreserved cell culture derived from bone marrow, tendon and adipose tissue had high membrane integrity indicators, colony formation and proliferation as well as the ability to directional adipogenic and chondrogenic differentiation. The analysis of immunophenotype showed that the tested cryopreserved MMSCs culture characterized by high levels of expression (≥90 %) of CD44, CD90, CD105, CD73 and low expression (≤1 %) of hematopoietic marker CD45. Cryopreserved bone marrow MMSCs were characterized by a high content of cells that synthesized type I collagen as compared to cultures which were derived from fat and tendon.Conclusions. Cell cultures derived from all studied sources have immunophenotype of precursor cells of mesenchymal origin. The MMSC of tendon tissue characterized by a greater capacity for colony formation and proliferation, and lower capacity for directed adipogenic differentiation, than MSCs from bone marrow and adipose tissue.