Analysis of human synovial and bone marrow mesenchymal stem cells in relation to heat-inactivation of autologous and fetal bovine serums

The Impact of Various Culture Conditions on Human Mesenchymal Stromal Cells Metabolism

In vitro and in vivo analyses are closely connected, and the reciprocal relationship between the two comprises a key assumption with concern to the conducting of meaningful research. The primary purpose of in vitro analysis is to provide a solid background for in vivo and clinical study purposes. The fields of cell therapy, tissue engineering, and regenerative medicine depend upon the high quality and appropriate degree of the expansion of mesenchymal stromal cells (MSCs) under low-risk and well-defined conditions. Hence, it is necessary to determine suitable alternatives to fetal bovine serum (FBS—the laboratory gold standard) that comply with all the relevant clinical requirements and that provide the appropriate quantity of high-quality cells while preserving the required properties. Human serum (autologous and allogeneic) and blood platelet lysates and releasates are currently considered to offer promising and relatively well-accessible MSC cultivation alternatives. Our study compared the effect of heat-inactivated FBS on MSC metabolism as compared to its native form (both are used as the standard in laboratory practice) and to potential alternatives with concern to clinical application—human serum (allogeneic and autologous) or platelet releasate (PR-SRGF). The influence of the origin of the serum (fetal versus adult) was also determined. The results revealed the key impact of the heat inactivation of FBS on MSCs and the effectiveness of human sera and platelet releasates with respect to MSC behaviour (metabolic activity, proliferation, morphology, and cytokine production).

The effect of foetal bovine serum supplementation upon the lactate dehydrogenase cytotoxicity assay: Important considerations for in vitro toxicity analysis

The lactate dehydrogenase (LDH) assay is a commonly-used tool for assessing toxicity in vitro. However, anecdotal reports suggest that foetal bovine serum (FBS) may contain LDH at concentrations significant enough to interfere with the assay and thus reduce its sensitivity. A series of experiments were performed to determine whether addition of FBS to culture medium significantly elevated culture media LDH content, and whether replacement of FBS with heat inactivated foetal bovine serum (HI-FBS) reduced LDH content and interfered with cell response to cytotoxic challenge. The addition of FBS at 5, 10 and 15% final concentrations increased culture medium LDH content in a dose-dependent manner. The substitution of HI-FBS for FBS reduced culture medium LDH content and increased the dynamic range of the assay. Cell viability of the SH-SY5Y human neuroblastoma and N27 rat mesencephalic neurone cell lines were significantly reduced as measured using the MTT reduction assay, whilst HI-FBS only affected toxicity response in a cell- and toxin-specific manner, although these effects were small. Hence, for cell lines with a high FBS requirement, the use of HI-FBS or alternative toxicity assays can be considered, or the use of alternative formulations, such as chemically-defined serum-free media, be adopted.

Noncoding RNAs: Possible Players in the Development of Fluorosis

Fluorosis is caused by excess of fluoride intake over a long period of time. Aberrant change in the Runt-related transcription factor 2 (RUNX2) mediated signaling cascade is one of the decisive steps during the pathogenesis of fluorosis. Up to date, role of fluoride on the epigenetic alterations is not studied. In the present study, global expression profiling of short noncoding RNAs, in particular miRNAs and snoRNAs, was carried out in sodium fluoride (NaF) treated human osteosarcoma (HOS) cells to understand their possible role in the development of fluorosis. qPCR and in silico hybridization revealed that miR-124 and miR-155 can be directly involved in the transcriptional regulation of Runt-related transcription factor 2 (RUNX2) and receptor activator of nuclear factor κ-B ligand (RANKL) genes. Compared to control, C/D box analysis revealed marked elevation in the number of UG dinucleotides and D-box sequences in NaF exposed HOS cells. Herein, we report miR-124 and miR-155 as the new possible players involved in the development of fluorosis. We show that the alterations in UG dinucleotides and D-box sequences of snoRNAs could be due to NaF exposure.

Meniscal repair possibilities using bone morphogenetic protein-7

This study analysed the influence of bone morphogenetic protein-7 (BMP-7) on cells and meniscal structure. The effect of treatment with BMP-7 was assessed in vitro and in vivo in lesions in the avascular area of the meniscus. Cells were extracted from the outer and inner part of eight menisci of four 2-year-old merino sheep. The menisci were digested with a collagenase mix, and meniscus cells of the synovium, vascular area and avascular area were extracted. The expression of genes for collagen (Col1 and Col2A), matrix metalloproteinases (MMP-2 and MMP-13) and aggrecan was analysed by real time quantitative polymerase chain reaction (qPCR) at baseline and after incubation with BMP-7. Eight sheep aged 2 years and weighing 35-40 kg were used for the in vivo study. Surgery was performed in both knees of every animal. Two holes were made in the avascular area of the medial meniscus of both knees and filled using Putty(®) (control groups) or OP-1 Putty(®), which comprises BMP-7 mixed with a cellulose putty carrier (experimental groups). Animals were sacrificed at 6, 12 and 25 weeks. Adding BMP-7 to vascular cells of the meniscus was associated with a 15-fold increase in Col2A expression and a 78-fold increase in BMP-7 expression. BMP-7 inhibited MMP-2 and MMP-13 expression. Adding BMP-7 to synovial cells inhibited the expression of Col1, doubled the expression of Col2A and reduced the expression of BMP-7; the expression of MMP-2 was inhibited, while that of MMP-13 was increased three-fold. Incubation of cells from the avascular region with BMP-7 was associated with a 2.4-fold increase in Col1 expression, and a 4.4-fold increase in Col2A expression compared with the control. The expression of MMP-2 and BMP-7 was inhibited. In the in vivo study, treatment of the holes in the avascular area of the meniscus with BMP-7 was associated with an important cell presence inside the holes and the appearance of fibrous tissue after 12 weeks; these features were not seen in the control groups. BMP-7 may be a suitable growth factor for stimulation of meniscal cell and collagen formation.

Differentiation of iPSC to Mesenchymal Stem-Like Cells and Their Characterization

Mesenchymal stem cells (MSC) are a unique population of adult stem cells that have the capacity to differentiate into numerous cell types as well as the ability to modulate the immune system. As such, MSC represent a promising stem cell population for use in the clinical treatment of a range of disorders involving tissue regeneration as well as the immune system. The lack of accessibility to MSC is currently limiting the use of MSC in mainstream clinical treatment strategies. It is therefore imperative for the future success of stem cell-based treatment approaches that are more reliable, and accessible sources of MSC are identified. The present chapter describes a method for generating MSC-like cells from induced pluripotent stem cells (iPSC), with equivalent growth and functional properties to parental MSC populations.

Serum-free media for the production of human mesenchymal stromal cells: a review

The regenerative potential of mesenchymal stromal cells (MSC) holds great promise in using them for treatment of a wide range of debilitating diseases. Several types of culture media and systems have been used for large-scale expansion of MSCs in vitro; however, the majority of them rely heavily on using foetal bovine serum (FBS)-supplement for optimal cell proliferation. FBS-based cultures pose the potential threat of spread of transmissible spongiform encephalopathy and bovine spongiform encephalopathy to MSCs and then to their recipients. A recent trend in cell culture is to change from serum-use to serum-free media (SFM). In this context, the current review focuses specifically on employment of various SFM for MSCs and discusses existences of various options with which to substitute FBS. In addition, we analyse MSC population growth kinetic patterns using various SFM for large-scale production of MSCs.

Stem cells derived from osteoarthritic knee mesenchymal tissues: a pilot study

Regenerative medicine is a promising approach for addressing musculoskeletal disorders. Successful implementation of regenerative therapies is based upon existence of reliable, easy accessible cell sources. Mesenchymal tissues removed during total knee replacement (TKR) were investigated as a potential autologous stem cell source. Materials and methods Samples were collected from patients undergoing primary TKR mononuclear cells from adipose and synovial tissue; subchondral trabecular bone and osteoarthritic cartilage were isolated and assessed in terms of mesenchymal stem cells (MSC) content. Results MSCs obtained from all the investigated tissue types and from all donors showed proliferative, differentiation and surface markers characteristic of stemness. Important number of MSCs could be obtained in the first passage (P0). Mesenchymal tissues removed during TJR can qualitatively and quantitatively function as autologous MSC sources to be considered for regenerative therapies.

Implantation of allogenic synovial stem cells promotes meniscal regeneration in a rabbit meniscal defect model

BACKGROUND

Indications for surgical meniscal repair are limited, and failure rates remain high. Thus, new ways to augment repair and stimulate meniscal regeneration are needed. Mesenchymal stem cells are multipotent cells present in mature individuals and accessible from peripheral connective tissue sites, including synovium. The purpose of this study was to quantitatively evaluate the effect of implantation of synovial tissue-derived mesenchymal stem cells on meniscal regeneration in a rabbit model of partial meniscectomy.

METHODS

Synovial mesenchymal stem cells were harvested from the knee of one New Zealand White rabbit, expanded in culture, and labeled with a fluorescent marker. A reproducible 1.5-mm cylindrical defect was created in the avascular portion of the anterior horn of the medial meniscus bilaterally in fifteen additional rabbits. Allogenic synovial mesenchymal stem cells suspended in phosphate-buffered saline solution were implanted into the right knees, and phosphate-buffered saline solution alone was placed in the left knees. Meniscal regeneration was evaluated histologically at four, twelve, and twenty-four weeks for (1) quantity and (2) quality (with use of an established three-component scoring system). A similar procedure was performed in four additional rabbits with use of green fluorescent protein-positive synovial mesenchymal stem cells for the purpose of tracking progeny following implantation.

RESULTS

The quantity of regenerated tissue in the group that had implantation of synovial mesenchymal stem cells was greater at all end points, reaching significance at four and twelve weeks (p < 0.05). Tissue quality scores were also superior in knees treated with mesenchymal stem cells compared with controls at all end points, achieving significance at twelve and twenty-four weeks (3.8 versus 2.8 at four weeks [p = 0.29], 5.7 versus 1.7 at twelve weeks [p = 0.008], and 6.0 versus 3.9 at twenty-four weeks [p = 0.021]). Implanted cells adhered to meniscal defects and were observed in the regenerated tissue, where they differentiated into type-I and II collagen-expressing cells, at up to twenty-four weeks.

CONCLUSIONS

Synovial mesenchymal stem cells adhere to sites of meniscal injury, differentiate into cells resembling meniscal fibrochondrocytes, and enhance both quality and quantity of meniscal regeneration.

Mesenchymal stem cells: from experiment to clinic

There is currently much interest in adult mesenchymal stem cells (MSCs) and their ability to differentiate into other cell types, and to partake in the anatomy and physiology of remote organs. It is now clear these cells may be purified from several organs in the body besides bone marrow. MSCs take part in wound healing by contributing to myofibroblast and possibly fibroblast populations, and may be involved in epithelial tissue regeneration in certain organs, although this remains more controversial. In this review, we examine the ability of MSCs to modulate liver, kidney, heart and intestinal repair, and we update their opposing qualities of being less immunogenic and therefore tolerated in a transplant situation, yet being able to contribute to xenograft models of human tumour formation in other contexts. However, such observations have not been replicated in the clinic. Recent studies showing the clinical safety of MSC in several pathologies are discussed. The possible opposing powers of MSC need careful understanding and control if their clinical potential is to be realised with long-term safety for patients.