CD31 characterization. Dye 7-amino-actinomycin D 7-AAD was added to assess the viability of cells. These include pain at the harvest site, and harvest of only a small volume of bone marrow and therefore a small number of MSCs , meaning that ex-vivo expansion of the cells is probably necessary to obtain clinically significant cell numbers.
By our protocol, it is possible to obtain, within about 2 hours, a mean of 8.
Our procedure differs from protocols previously described in literature e. This is not necessary with our protocol.
There are no studies establishing fetal bovine serum security as regard its clinical use. Our isolation procedure is performed step by step by a closed circuit system, in the same operating theatre of the liposuction procedure, thus minimizing the risks of contamination. Neither serum nor animal-derived reagents are used, making this strategy easier, cheaper, and safer, minimizing the possibility of immune reactions.
The harvesting of ASCs offers several advantages over BM-MSCs: abundant donor tissue, plentiful number of cells, patient compliance, ease of procedure, minimal postoperative complication rate, and no need for cell culture or amplification. Since the number of cells rapidly decreases after the first aspiration, the BM-MSCs obtained by aspiration of 10—40 mL of bone marrow from the iliac crest ranges from 1.
Complication mainly: hematoma, seroma, infection rate of liposuction is low 0. Based on our protocol, the number of stem cells derivable from adipose tissue is fold more than the number derivable from bone marrow. Bearing in mind that it is not unusual to lipoaspirate 1 L and much more of adipose tissue, the number of obtainable ASCs may be further multiplied by a factor of 20 about 1. Click here to see the Library ]; moreover, cell amplification procedures must follow strict legislative protocols, rely on certified Good Manufacturing Practice GMP laboratories, require two operative procedures, and are very expensive.
Mesenchymal stem cells in bone development, bone repair, and skeletal regeneration therapy.
Mutations and carcinogenic effects have never been described; however, lack of description does not mean lack of effect, and this eventuality cannot be excluded. A practical example of surgical application could be represented by symptomatic clavicular delayed unions or clavicular non-unions.
In the first scenario a simple percutaneous injection of purified, vital ASCs could be carried out under sonographic guide, directly into the fracture site. As Filardo et al. Chondrogenesis comparable to BM-MSCs can be induced from ASCs only using considerable doses of growth factors, thus making the application of ASCs for cartilage tissue-engineering poorly reproducible in vivo and expensive.
The described technique is designed to inject cells for bone loss correction, but it is not suited for the treatment of surface loss, such as cartilaginous ones. The procedure we describe is easy, fast, economic, and safe. Since it allows for the harvesting of a significant number of ASCs ready for intraoperative use , we hope it might represent a useful advance in terms of regenerative procedures involving bone defects. Anyhow it should be stressed that although it is not possible to assess the rate of survival of ASCs after injection in vivo in human subjects in the following days or weeks, a significative postoperative death rate of transplanted stem cells have to be expected.
Stem cell transplantation for articular cartilage repair
Manassero et al. These results indicated that MSCs promote bone formation despite early and massive cell death. A major drawback of the technique, compared to lab-processed samples, is the lack of control of the quality of the sample before grafting. You can search by either catalog number or antibody name. MSCs are multipotent stem cells. Below are a few facts about MSCs 1 :. They are known to regenerate structure and connective tissues, repair bones 2 and cartilage 3 , stimulate angiogenesis 4 after heart attacks , and reduce inflammation and scarring through their immunomodulatory properties 5.
They can also be found in adipose tissue, amnion, synovial fluids, muscles, dermis, deciduous teeth, and umbilical cord tissue. The number of cells obtained from a donor is insufficient to be able to produce a fully matured organ.
Because of this, MSCs need to be grown and expanded in vivo with controlled media and specific growth factors in order to undergo senescence after 8—10 passages 1 , 6. MSCs are multipotent stem cells that are able to differentiate into a variety of different cells. The four main types are adipocytes, myocytes, chondrocytes, and osteocytes Figure 1.
The Promotional Effect of Mesenchymal Stem Cell Homing on Bone Tissue Regeneration
MSCs are long, thin, and widely dispersed. Figure 1. The multipotent potential of MSCs. Exposure to different inductive agents e. Commonly, MSCs are thought to be true stem cells as they can undergo self-renewal and differentiation into a plethora of tissues of the mesenchymal lineage 6. However, MSCs are a particular type of pre-differentiated stem cells. They remain undifferentiated, but they are not true stem cells. Figure 2 contains further detail on the differentiation pathways of embryonic stem cells ESCs and induced pluripotent stem cells iPSCs.
Figure 2. ESCs and iPCs differentiate into ectoderm, mesoderm, and endoderm lineages. Depending on the environment MSCs grow in, they can give rise to a variety of lineage-specific cell types. Research into MSC's has exploded in recent years. The most commonly used source of MSC's is bone marrow aspirate. Most of the adult bone marrow consists of blood cells in various stages of differentiation.
The adult stem cell fraction is present in the nucleated cells of the marrow. As a result, that leaves the very small number of MSC's in the marrow as cells capable of differentiating into tissues of interest to joint preservation.
Marrow nucleated cells are used every day in regenerative orthopedics. The knee microfracture surgery technique relies on the release of these cells into a cartilage lesion to initiate fibrocartilage repair in osteochondral defects. Again, these techniques produce a very dilute MSC population, usually a yield of 1 in 10,—1,, of the nucleated cells. Once these MSCs are ready for re-implanation, they are usually transferred with growth factors to allow for continued cell growth and engraftment to the damaged tissue.
At some point, a signal is introduced either in culture or after transplant to the damaged tissue for the cells to differentiate into the end tissue in this discussion, cartilage. Until recently, the use of cultured mesenchymal stem cells to regenerate cartilage has been primarily in research with animal models. There are now, however, two published case reports of the above technique being used to successfully regenerate articular and meniscus cartilage in human knees.
Another team used a similar technique for cell extraction and ex vivo expansion but cells were embedded within a collagen gel before being surgically re-implanted.
They reported a case study in which a full-thickness defect in the articular cartilage of a human knee was successfully repaired.