Accelerated and safe expansion of human mesenchymal stromal cells in animal serum-free medium for transplantation and regenerative medicine.
ABSTRACT Human bone marrow mesenchymal stromal cells (hMSC) are currently investigated for a variety of therapeutic applications. However, most expansion protocols still use fetal calf serum (FCS) as growth factor supplement which is a potential source of undesired xenogeneic pathogens. We established an expansion protocol for hMSC based on the use of GMP-produced basic medium LP02 supplemented with 5% of platelet lysate (PL) obtained from human thrombocyte concentrates. Compared to FCS-supplemented culture conditions, we found a significant increase in both colony forming unit-fibroblast (CFU-F) as well as cumulative cell numbers after expansion. This accelerated growth is optimized by pooling of at least 10 thrombocyte concentrates. A minimal requirement is the use of 5% of PL with an optimal platelet concentration of 1.5 x 10(9)/ml, and centrifugation of thawed lysate at high speed. Cells expanded by this protocol meet all criteria for mesenchymal stromal cells (MSCs), e.g. plastic adherence, spindle-shaped morphology, surface marker expression, lack of hematopoietic markers, and differentiation capability into three mesenchymal lineages. MSC at passage 6 were cytogenetically normal and retained their immune-privileged potential by suppressing allogeneic reaction of T-cells. Additionally, gene expression profiles show increased mRNA levels of genes involved in cell cycle and DNA replication and downregulation of developmental and differentiation genes, supporting the observation of increased MSC-expansion in PL-supplemented medium. In summary, we have established a GMP-compatible protocol for safe and accelerated expansion of hMSC to be used in cell and tissue therapy.
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ABSTRACT: Human mesenchymal stem cells (hMSCs), also referred to as multipotent stromal cells, are currently being applied in clinical trials for bone diseases, graft versus host disease, and myocardial infarction. However, the standard growth medium for hMSCs contains 10%-20% fetal calf serum (FCS), and FCS is strongly immunogenic in both rodents and humans. Previously, we reported that by a sensitive fluorescence-based assay, 7-30 mg of internalized FCS is associated with 10(8) hMSCs, a dosage that will probably be needed for most therapies. We also found that a brief culture in medium containing autologous 20% adult human serum (AHS) or autologous 10% AHS supplemented with growth factors (AHS(+)) reduced the contamination by more than 99.9%. We have now extensively characterized the culture conditions and shown that hMSC expansion is possible using heterologous 20% AHS or heterologous 10% AHS(+). The uptake of FCS is an active process that acts to concentrate contamination in the cells even under low serum conditions (2% FCS) but can be actively displaced by incubation of the cells in medium with AHS. Rat MSCs (rMSCs) can be expanded under similar conditions using supplemented heterologous adult rat serum (ARS(+)). After expansion in FCS, a further 8 days of culture with ARS(+) significantly improves the viability of the rMSCs in vivo after encapsulation in fibrin followed by subcutaneous implantation in rats. Our results have the potential to dramatically improve cellular and genetic therapies using hMSCs.Stem Cells 11/2006; 24(10):2232-43. · 7.70 Impact Factor
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ABSTRACT: Mesenchymal stem cells (MSC) have immunomodulatory effects. The aim was to study the effect of MSC infusion on graft-versus-host disease (GVHD). We gave MSC to eight patients with steroid-refractory grades III-IV GVHD and one who had extensive chronic GVHD. The MSC dose was median 1.0 (range 0.7 to 9)x10(6)/kg. No acute side-effects occurred after the MSC infusions. Six patients were treated once and three patients twice. Two patients received MSC from HLA-identical siblings, six from haplo-identical family donors and four from unrelated mismatched donors. Acute GVHD disappeared completely in six of eight patients. One of these developed cytomegalovirus gastroenteritis. Complete resolution was seen in gut (6), liver (1) and skin (1). Two died soon after MSC treatment with no obvious response. One of them had MSC donor DNA in the colon and a lymph node. Five patients are still alive between 2 months and 3 years after the transplantation. Their survival rate was significantly better than that of 16 patients with steroid-resistant biopsy-proven gastrointestinal GVHD, not treated with MSC during the same period (P = 0.03). One patient treated for extensive chronic GVHD showed a transient response in the liver, but not in the skin and he died of Epstein-Barr virus lymphoma. MSC is a very promising treatment for severe steroid-resistant acute GVHD.Transplantation 06/2006; 81(10):1390-7. · 3.78 Impact Factor
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ABSTRACT: Studies on new procedures for bone reconstruction suggest that autologous cells seeded on a resorbable scaffold can improve the treatment of bone defects. It is important to develop culture conditions for ex vivo expansion of stromal stem cells (SSC) that do not compromise their self-renewing and differentiation capability. Bone marrow SSC and platelet gel (PG) obtained by platelet-rich plasma provide an invaluable source for autologous progenitor cells and growth factors for bone reconstruction. In this study the effect of platelet-rich plasma (PRP) released by PG on SSC proliferation and differentiation was investigated. MTT assay was used to investigate the effect of PRP on proliferation: results showed that PRP induced SSC proliferation. The effect was dose dependent and 10% PRP is sufficient to induce a marked cell proliferation. Untreated cells served as controls. Upon treatment with 10% PRP, cells entered logarithmic growth. Removal of PRP restored the characteristic proliferation rate. Because SSC can gradually lose their capability to differentiate along the chondrogenic and osteogenic lineage during subculture in vitro, we tested whether 10% PRP treatment affected SSC ability to mineralize. SSC were first exposed to 10% PRP for five passages, at passage 6 PRP was washed away and plated cells were treated with dexamethasone (DEX). DEX induced a three-fold increase in the number of alkaline phosphatase positive cells and induced mineralization that is consistent with the differentiation of osteochondroprogenitor cells. In conclusion, 10% PRP promotes SSC proliferation; cells expanded with 10% PRP can mineralize the extracellular matrix once PRP is withdrawn.Biomaterials 09/2003; 24(18):3095-100. · 7.60 Impact Factor