MesenchymalStemCells (MSC), also termed Mesenchymal Stromal Cells, are self-renewing multipotent cells that can differentiate into a wide variety of cell types. MSC have been shown to differ- entiate in vitro into adipocytes, chon- drocytes, osteoblasts, myocytes, and ß-pancreatic islets cells. They can also transdifferentiate into neuronal cells and hepatocytes.
Mesenchymalstemcells have been found in various tissues and act as source for renewal and repair. The mouse incisor tooth continuously grows throughout life, implicating that there are stem cell niches constantly contributing with cells. The composition of these stem cell niches is not fully understood. Here, we show that Schwann cells on the peripheral nerves in the close proximity to the incisor tooth constitute a stem cell niche. Transgenic mouse models were used to label Schwann cells and their progeny in vivo. It was also possible to establish that Schwann cell precursors contributed in tooth development during embryogenesis. In the adult incisor tooth, it was demonstrated that there were a continuous replenishment from Schwann cells with dental mesenchymalstemcells and odontoblasts. Moreover, through a multi-color reporter line mouse model it was possible to label individual Schwann cells and show their specific contribution and dynamics to tooth organogenesis in adulthood. The dental mesenchymalstemcells were arranged in highly spatialized domain patterns and competed for the opportunity to form odontoblasts. Furthermore, after tooth injury these Schwann cell-derived dental mesenchymalstemcells could be recruited for repair. Thus, these results advocate a novel source of dental mesenchymalstemcells, the peripheral Schwann cells, that throughout life contribute to tooth growth and become involved in regeneration after tooth damage. This might have important implications for the further understanding of adult stem cell populations and their potential use in tissue engineering.
A consequence of this is that all mesenchymalstemcells are now considered to be the same, regardless of their tissue of origin, to the extent that mesenchymalstemcells from widely different tissues are often considered equivalent in clinical applications. A defining feature of these cells is their generic multipotent differentiation in vitro into osteoblasts, chondrocytes and adipocytes; however, recent in vivo research clearly shows that mesenchymalstemcells have different origins, properties and functions in different tissues that are not well reflected in vitro. Thus, the crude directed differentiation of mesenchymalstemcells in vitro misses key subtleties that exist in vivo. It is only recently that genetic lineage tracing has been used to identify mesenchymalstemcells and their properties in vivo. These approaches are now the ‘ gold standard ’ for identifying stemcells and this needs to be recognized over their in vitro properties. In vitro definitions are still important for standardising cell characteristics, particularly in relation to possible therapeutic uses, but such definitions are not appropriate for cells in vivo.
There is growing interest in TRPC channels in adult stemcells and other cells with high proliferative and differentiation capacities. For instance, the expression of TRPC1 was recently demonstrated in primary umbilical cord blood CD34 + cells  and in the C2C12 myoblast line, where it is involved in the initial phase of differentiation . However, little is known about the expression of the TRPC subfamily members in mesenchymalstemcells (MSC) possessing high proliferative and differentiation potentials. Here, we provide the first proof that some TRPC family members are expressed in MSC and that they may further play a role in stem cell proliferation.
Ramesh R., Madhan Jeyaraman * , Kartavya Chaudhari, Hardik J. Dhamsania, Prajwal G. S.
Department of Orthopedics, JJM Medical College, Davangere, India
Percutaneous administration of “Orthobiologics” offers the advantage of ac- celerated and functional recovery of musculoskeletal disorders. Stem cell op- timizes the biological healing of diseases. The regenerative capacity of mesen- chymal stemcells provides a pavement for clinicians to build up an organ of interest in vitro . Mesenchymalstemcells remain the perfect cell based tissue regeneration modality for treatment of musculoskeletal disorders in a mini- mally invasive environment without any significant morbidity. This article outlines the applications of mesenchymalstem cell administration in various musculoskeletal disorders.
Cellular therapy has evolved quickly over the last decade both at the level of in vitro and in vivo preclinical research and in clinical trials. Embryonic stemcells and non-
embryonic stemcells have all been explored as potential therapeutic strategies for a number of diseases. One type of adult stemcells, mesenchymalstemcells, has generated a great amount of interest in the field of regenerative medi- cine due to their unique biological properties. MSCs were first discovered in 1968 by Friedenstein as an adherent fibroblast-like population in the bone marrow capable of differentiating into bone . It was subsequently shown that MSCs can be isolated from various tissues such as adipose tissue, peripheral blood, umbilical cord and placenta. These cells have a remarkable capacity of extensive in vitro expan- sion which allows them to rapidly reach the desired number for in vivo therapy . Different laboratories have identified, under partly different isolation or culture conditions, MSCs with specific properties. For better characterization of MSC, in 2006, the International Society of Cellular Therapy defined MSCs by the following three criteria :
Mesenchymalstemcells (MSC) are multipotent cells found as part of the stromal compartment of the bone marrow and in many other organs. They can be identified in vitro as CFU-F (colony forming unit-fibroblast) based on their ability to form adherent colonies of fibroblast-like cells in culture. MSC expanded in vitro retain characteristics appropriate to their tissue of origin. This is reflected in their propensity for differentiating towards specific lineages, and their capacity to generate, upon retransplantation in vivo, a stroma supporting typical lineages of hematopoietic cells. Hox genes encode master regulators of regional specification and organ development in the embryo and are widely expressed in the adult. We investigated whether they could be involved in determining tissue-specific properties of MSC. Hox gene expression profiles of individual CFU-F colonies derived from various organs and anatomical locations were generated, and the relatedness between these profiles was determined using hierarchical cluster analysis. This revealed that CFU-F have characteristic Hox expression signatures that are heterogeneous but highly specific for their anatomical origin. The topographic specificity of these Hox codes is maintained during differentiation, suggesting that they are an intrinsic property of MSC. Analysis of Hox codes of CFU-F from vertebral bone marrow suggests that MSC originate over a large part of the anterioposterior axis, but may not originate from prevertebral mesenchyme. These data are consistent with a role for Hox proteins in specifying cellular identity of MSC.
MI NI - R EVIEW
Cell therapy has been considered as the third pillar of medicine. There are several kinds of cells attracted researchers attention whereas the growing interest in mesenchymalstemcells (MSCs) for regenerative purposes has enabled them to explore the versatile characteristics for regenerative purposes. So far, near about 5000 clinical trials using MSCs, authenticating the clinical applicability of these cells. Their multipotent differentiation and unique immunosuppressive properties have made them ideal candidate in cell therapeutic approaches. Recent advances have been observed in the homing of these cells to enhance their transplantation efficacy. These cells have been proposed as the ideal candidates for cancer therapy and have been engineered for targeted cancer therapy. Their successful applications and responses have termed them the ideal cells for the future of regenerative medicine.
Received June 7 th , 2010; revised July 15 th , 2010; accepted July 20 th , 2010 .
Although stem cell therapies have been proposed as a candidate for treating neurological diseases, the best stem cell source and their therapeutic efficacy remain uncertain. Embryonic stemcells (ESCs) can efficiently generate multiple cell types, but pose ethical and clinical challenges, while the more accessible adult stemcells have a limited develop- mental potential. Following included-expression of Nanog, an ESC gene, adult human mesenchymalstemcells (HMSCs) are able to develop into cells exhibiting neural cell-like characteristics based on morphology, cell markers, and gene expressions. After expansion, Nanog overexpressed HMSCs differentiated into cells immunopositive for III-tubulin and glial fibrillary acidic protein, lineage markers for neurons and astrocytes, respectively, under the influence of con- ditional media from differentiated human neural stemcells. This result indicates that the Nanog expression increased the ability of HMSCs to become a neural cell lineage. We further demonstrated that Nanog-overexpressed HMSCs were able to survive, migrate, and undergo neural cell-like differentiation after transplantation in vivo. This data offers an exciting prospect that peripheral adult stemcells can be modified and used to treat neurological diseases.
3. StemCells as a “Biological Solution to a Biological Problem”
Stemcells are unspecialized cells in the body that retain the ability to generate cells of undifferentiated state identical to themselves, or of differentiating into other types of body cells with specialized functions . There are various types of stemcells such as embryonic stemcells (ESCs), hematopoietic stemcells (HSCs), neural stemcells (NSCs), mesenchymalstemcells (MSCs) and induced pluripotent stemcells (iPSCs) . Nowadays, with the great progression of biology and biotechnology, we are exploring “biological solutions to biological problems”. Stem cell therapy in axonal demyelination and neurological disability has had promising results in animal models as well as human patient clinical treatment . Stem cell therapies may serve as potential therapy for neurodegenerative disease. Here, we review the recently published studies regarding preclinical and clinical use of MSCs and iPSCs in the treatment of MS, and their therapeutic mechanisms. Among the various types of stemcells, the efficacy and safety of MSCs have long been well established and characterized, but the recent advancements of iPSCs make them a promising candidate for autologous therapy. Both MSCs and iPSCs can be obtained from patients relatively easily and can be expanded for use.
Mesenchymalstemcells (MSCs) have emerged as a promising tool for treating autoimmune dacryoadenitis, owing to their immunosuppressive properties, tissue repair functions, and powerful differentiation capabilities. A large number of studies have focused on the effect of MSCs on autoimmune diseases, such as autoimmune uveitis, inflammatory bowel disease, and collagen-induced arthritis, but few studies have, to date, unequivocally established the efficacy of MSCs for treating autoimmune dacryoadenitis. In this review, we discuss recent advances in MSC treatment for autoimmune dacryoadenitis.
Biology of mesenchymalstemcells
In addition to having multi-lineage differentiation capacity, multi-potent stromal cells obtained from bone marrow and other tissues possess several properties that are unique to these cells in order to bring about tissue regeneration. In particular, BMSCs are known to prefer- entially home and accumulate to the site of injury and inflammation. The SDF1/CXCR pathway is a key regu- lator for BMSC migration, and, in the absence of SDF1 signal, migration of these cells to the bone tissue has been found to be impaired [29,30]. These cells are also known to secrete a large number of growth factors, cytokines, and chemokines that carry out different functions. This paracrine activity of MSCs obtained from various sources is thought to be one of the major means by which these cells mediate anti-inflammatory, anti-apoptotic, anti- fibrotic, angiogenic, mitogenic, and wound-healing
Chapter 3: Differentiation potential of mesenchymalstemcells and their labelling methods
The aim of the study is to investigate the potential of MSC to contribute to kidney development in an in vitro model of nephrogenesis. Accordingly, the capacity of MSCs to become integrated into developing renal structures and their subsequent differentiation into specific kidney phenotypes will be tested. The objective of the first part of the chapter is therefore to demonstrate multilineage differentiation potential of MSCs employed in this study by performing adipogenic, osteogenic and chondrogenic differentiation assays. The ability of MSCs to undergo in vitro adipogenesis, osteogenesis and chondrogenesis upon stimulation with appropriate inductive medium is widely used for identification and characterisation of MSC populations (Pittenger et al. 1999; Peister et al. 2004). Nevertheless, different MSC populations might differ substantially in their differentiation potential (Peister et al. 2004; Anjos-Afonso and Bonnet 2007). It has been described that MSCs isolated from various mouse strains have different abilities to differentiate (Phinney et al. 1999; Peister et al. 2004). It was demonstrated that bone marrow-derived MSCs isolated from Bl/6 mice more readily undergo osteogenic differentiation than from BALB/c mice which in turn have higher adipogenic potential. MSCs isolated from Bl/6 and BALB/c have also lower chondrogenic potential in comparison with MSCs derived from FVB/N and DBA1 mice (Peister et al. 2004). In addition, over time the number of broad flattened and slowly growing cells increases over rapidly expanding spindle-shaped cells in the MSC culture (Digirolamo et al.
Mesenchymalstem cell (MSC) therapy offers great potential for treatment of disease through the multifunctional and responsive ability of these cells. In numerous contexts, MSC have been shown to reduce inflammation, modulate immune responses, and provide trophic factor support for regeneration. While the most commonly used MSC source, the bone marrow provides relatively little starting material for cellular expansion, and requires invasive extraction means, fibroblasts are easily harvested in large numbers from various biological wastes. Additionally, in vitro expan- sion of fibroblasts is significantly easier given the robustness of these cells in tissue culture and shorter doubling time compared to typical MSC. In this paper we put forward the concept that in some cases, fibroblasts may be utilized as a more practical, and potentially more effective cell therapy than mesenchymalstemcells. Anti-inflammatory, immune modulatory, and regenerative properties of fibroblasts will be discussed in the context of regenerative medicine.
Regarding tendons, the application of MSCs increase collagen fiber density, enhance tissue architecture and increase biomechanical strength. Due to the mesenchy- mal origin of these cells, they have been used to facilitate tendon tissue regeneration, but several questions concern- ing the clinical use of MSCs have been raised. Safety concerns about the use of mesenchymalstemcells in terms of their immunosuppressive effect, their possible genetic transformation and their manufacture for clinical use (expansion, phenotype and genetic stability in culture, cryopreservation and banking, microbial contamination) should be carefully considered . In the face of many promising experimental and preclinical results, additio- nal questions regarding the role of MSCs in the tendon healing process need to be addressed in order to achieve a better understanding of native tendon healing, the sig- nal pathways for inducing tissue regeneration, and the molecular signaling for MSC differentiation. An interdis- ciplinary approach, including basic research in biology, bioengineering and clinical research, is required to achie- ve the successful clinical transfer of MSC treatment in tendon regeneration.
Keywords: Mesenchymalstemcells, Toxicant, Etiology, Pharmacokinetics.
Toxicity may result due to administration or exposure to drugs or chemicals or xenobiotic compounds or radiation or particulate matter or endogenous production of toxins by any microbial flora or transplanted cells. Such primary and auxiliary toxic agents may disrupt intracellular cell signaling and interrupt cell-to- cell interactions from intra- and extra-cellular communiqué and affect cellular architectures in biochemical, anatomical, cellular, psychological, and pathological level. This may be due to the complex interaction established between toxic agents and genes, proteins, RNA and cellular organelles [1,2]. These phenomena may alter biological cascades of circadian rhythm in human, affect the dynamic cellular function and metabolism, generate malignant tissues, change rhythmic beating passion of heart and can provoke psychological complications . In the pharmaceutical settings, toxicological studies of new compounds or agents play the most key role to provide safety and accurate assessment of risk factors associated with novel drugs before administration to human beings. The US Food and Drug Administration states that it is essential to screen new molecules for pharmacological activity and toxicity potential in animals (21CFR Part 314) . Traditionally, various animal models such as mice, rats, guinea pigs, and dogs are used to predict or anticipate toxicity of newly synthesized drugs or stringent chemicals or any suspected agents, as these agents might induce cardiotoxicity, hepatotoxicity, genotoxicity or epigenetic and reproductive toxicity in humans.
Abstract: Mesenchymalstemcells (MSCs) are being developed for stem cell therapy and can be efficiently used in regenerative medicine. To date, more than 1,000 clinical trials have used MSCs; of these, more than 80 clinical trials have targeted liver disease. MSCs migrate to damaged liver tissues, differentiate into hepatocytes, reduce liver inflammatory responses, reduce liver fibrosis, and act as antioxidants. According to the reported literature, MSCs are safe, have no side effects, and improve liver function; however, their regenerative therapeutic effects are unsatisfactory. Here, we explain, in detail, the basic therapeutic effects and recent clinical advances of MSCs. Furthermore, we discuss future research directions for improving the regenerative therapeutic effects of MSCs.
In several preclinical studies with different critical-size defects in the meniscus, the application of mesenchymalstemcells could significantly enhance meniscus regeneration compared to empty defects or to cell-free biomaterials.
Regenerative treatment of meniscus with mesenchymalstemcells seems to be a promising approach to treat meniscal tears and defects. However it is still not clear, whether the stem cell effect is a direct action of the mesenchymal-based cells or is rather mediated by secretion of certain stimulating factors. The missing knowledge of the underlying mechanism is one of the reasons for regulatory burdens to permit these stem cell-based strategies in clinical practice. Other limitations are the necessity to expand cells prior to transplantation resulting in high treatment costs. Alternative treatment modalities, which use growth factors concentrated from peripheral blood aspirates or mononucleated cells concentrated from bone marrow aspirates, are currently in development in order to allow an attractive one-step procedure without the need for cell expansion in cultures and thus lower efforts and costs.