Age-related decline in the osteogenic potential of human bone marrow cells cultured in three-dimensional collagen sponges

Immunosuppressive properties of mesenchymal stromal cells derived from amnion, placenta, Wharton's jelly and umbilical cord

BACKGROUND

The role of bone marrow-derived mesenchymal stromal cells (BM-MSC) in preventing the incidence and ameliorating the severity of graft-versus-host disease (GvHD) has recently been reported. However, as the collection of BM-MSC is an invasive procedure, more accessible sources of MSC are desirable.

AIM

This study aimed to explore the alternative sources of MSC from amnion, placenta, Wharton's jelly and umbilical cord, which are usually discarded.

METHODS

MSC from those tissues were isolated using mechanical dissociation and enzymatic digestion. Their capacity for proliferation and differentiation, and ability to suppress alloreactive T-lymphocytes were studied and compared with those of BM-MSC.

RESULTS

MSC derived from amnion, placenta, Wharton's jelly and umbilical cord were similar to BM-MSC regarding the cell morphology, the immunophenotype as well as the differentiation ability. These MSC also elicited a similar degree of immunosuppression, as evidenced by the inhibition of alloreactive T-lymphocytes in the mixed lymphocyte reaction, compared with that of BM-MSC. MSC from umbilical cord and Wharton's jelly had a higher proliferative capacity, whereas those from amnion and placenta had a lower proliferative capacity compared with BM-MSC.

CONCLUSION

The results obtained from this study suggest that MSC from amnion, placenta, Wharton's jelly and umbilical cord can therefore be potentially used for substituting BM-MSC in several therapeutic applications, including the treatment of GvHD.

Human induced pluripotent stem cell-derived mesenchymal stem cell seeding on calcium phosphate scaffold for bone regeneration

Tissue engineering provides an important approach for bone regeneration. Calcium phosphate cement (CPC) can be injected to fill complex-shaped bone defects with excellent osteoconductivity. Induced pluripotent stem cells (iPSCs) are exciting for regenerative medicine due to their potential to proliferate and differentiate into cells of all three germ layers. To date, there has been no report on iPSC seeding with CPC scaffolds. The objectives of this study were to (1) obtain iPSC-derived mesenchymal stem cells (iPSC-MSCs); (2) seed iPSC-MSCs on CPC scaffold for the first time to investigate cell attachment and proliferation; and (3) investigate osteogenic differentiation of iPSC-MSCs on CPC and mineral synthesis by the cells. iPSCs were derived from adult marrow CD34+ cells that were reprogrammed by a single episomal vector pEB-C5. iPSCs were cultured to form embryoid bodies (EBs), and MSCs were migrated out of EBs. Flow cytometry indicated that iPSC-MSCs expressed typical surface antigen profile of MSCs. Mesenchymal differentiation of iPSC-MSCs demonstrated that the iPSC-MSCs had the potential to differentiate into adipocytes, chondrocytes, and osteoblasts. iPSC-MSCs had good viability when attached on CPC scaffold. iPSC-MSCs differentiated into the osteogenic lineage and synthesized bone minerals. iPSC-MSCs on CPC in osteogenic medium yielded higher gene expressions of osteogenic markers including alkaline phosphatase (ALP), osteocalcin, collagen type I, and Runt-related transcription factor 2 than those in control medium (p<0.05). iPSC-MSCs on CPC in osteogenic medium had 10-fold increase in ALP protein than that in control medium (p<0.05). Bone mineral synthesis by iPSC-MSCs adherent to CPC scaffold was increased with time, and mineralization in osteogenic medium was three to four fold that in control medium. In conclusion, iPSCs were derived from adult marrow CD34+ cells that were reprogrammed by a single episomal vector pEB-C5, and MSCs were generated from the EBs. iPSC-MSCs showed good viability and osteogenic differentiation on CPC scaffold for the first time; hence, the novel iPSC-MSC-CPC construct is promising to promote bone regeneration in dental, craniofacial, and orthopedic repairs.

Immunophenotypic comparison of heterogenous non-sorted versus sorted mononuclear cells from human umbilical cord blood: a novel cell enrichment approach

Human umbilical cord blood (hUCB) has been the preferred source of stem cells for the treatment of haematological malignancies and genetic disorders. This is primarily due to its non-invasiveness, high accessibility with relative ease of isolation. Still failures do prevail due to its heterogeneity and lesser frequency of MSC identified in UCB. This study, thus, employs a cell enrichment technology to improve its therapeutic efficacy. This was achieved by immunophenotypic comparison of stem cells isolated from the heterogenous non-sorted mononuclear cells (MNCs), linage depleted (Lin+ and Lin-) fractions obtained from magnetic activated cell sorter (MACS) and sorted MNCs obtained by fluorescent activated cell sorter (FACS). The markers under consideration were CD29, CD44, CD34, CD45, CD133, CD90 and CD117. FACS sorted MNCs were rich in naive stem cell population, whereas non-sorted MNCs and lineage depleted fractions were found to be rich in progenitors. Thus, we suggest that a combination therapy of both sorted population might serve as an alternative valuable tool in treating haematologic/genetic disorders. However, further research on cell enrichment technology might give a clue for improved cell based therapy in regenerative medicine.

Promising perspectives towards regrowing a human arm

Despite the great enthusiasm about tissue engineering during the 1980s and the many significant basic observations made since then, the clinical application of tissue-engineered products has been limited. However, the prospect of creating new human tissues and organs is still exciting and continues to be a significant challenge for scientists and clinicians. A human arm is an extremely complicated biological construction. Considering regrowing a human arm requires asking about the current state-of-the-art of tissue engineering and the real capabilities that it may offer within a realistic time horizon. This work briefly addresses the state-of-the-art in the fields of cells and scaffolds that have high regenerative potential. Additional tools that are required to reconstruct more complex parts of the body, such as a human arm, seem achievable with the already available more sophisticated culture systems including three-dimensional organization, dynamic conditions and co-cultures. Finally, we present results on cell differentiation and cell and tissue maturation in culture when cells are exposed to mechanical forces. We postulate that in the foreseeable future even such complicated structures such as a human arm will be regrown in full in vitro under the conditions of a mechanically controlled co-culture system.

Osteogenic potentials of osteophytes in the cervical spine compared with patient matched bone marrow stromal cells

BACKGROUND

Osteophytes that form adjacent to degenerated disc have osteogeic potential. Studies suggest that their formation is associated with mesenchymal precursors arising from the chondrosynovial junction. This study is aimed to determine the cellular aging and osteogenic differentiation potential of osteophyte-derived mesenchymal cells (oMSCs) when compared to patient-matched bone marrow stromal cells (bMSCs).

MATERIALS AND METHODS

oMSCs and bMSCs were isolated from tissue samples during anterior cervical discectomy and fusion surgery. Extensive expansion of cell cultures was performed and early and late passage cells (P4 and P9, respectively) were used to study cell senescence and telomerase activity. Furthermore, osteogenic differentiation was applied to detect their osteogenic capacity.

RESULTS

The proliferation capacity of oMSCs in culture was superior to that of bMSCs and these cells readily underwent osteogenic differentiation. Our results showed that oMSCs had higher telomerase activity in late passages compared with bMSCs, although there was no significant difference in the telomerase activity in the early passages in either cell types. The telomerase activity was detectable only in early passage oMSCs and not in bMSCs.

CONCLUSIONS

Our results indicate that oMSCs retain a level of telomerase activity in vitro, which may account for the relatively greater longevity of these cells, compared to bMSCs. Furthermore, when compared to bMSCs, oMSCs maintained a higher proliferative capacity and the same osteogenic capacity, which may offer new insights of tissue formation.

Comparison of different methods for the isolation of mesenchymal stem cells from umbilical cord matrix: proliferation and multilineage differentiation as compared to mesenchymal stem cells from umbilical cord blood and bone marrow

We have identified the most appropriate method of isolating human umbilical cord matrix-derived mesenchymal stem cells (UCM-MSCs) and compared morphological, phenotypic, proliferative, and differentiation characteristics of UCM-MSCs with bone marrow-derived MSCs (BM-MSCs) and umbilical cord blood-derived MSCs (UCB-MSCs). Three explant culture methods and 3 enzymatic methods were compared with regards to time for primary culture, cell number, cell morphology, immune phenotype, and differentiation potential. Morphological, phenotypic, proliferative, and differentiation characteristics of UCM-MSCs, BM-MSCs, and UCB-MSCs were also compared. UCM-MSCs isolated using the 10 mm size tissue explant method led to shorter primary culture time, higher numbers of isolated cells, and higher proliferation rates compared with other isolation methods. Immune phenotype and multilineage differentiation capacity did not differ significantly among 6 groups. UCM-MSCs had similar characteristics as BM-MSCs and UCB-MSCs, including fibroblastic morphology, typical immunophenotypic markers, and multilineage differentiation capacity. In comparison with UCB-MSCs and BM-MSCs, UCM-MSCs have higher proliferative capacity, higher rate of chondrogenic differentiation, and higher expression of CD 146. The results suggest that the 10 mm size tissue culture method is the optimal protocol for the isolation of UCM-MSCs. Given the distinct advantages of UC, such as accessibility, painless acquisition, and abundance of cells obtained, we propose that UC be considered an alternative to BM and UCB as a source of MSCs for cell therapy.

Bone formation in calvarial defects by injectable nanoparticular scaffold loaded with stem cells

OBJECTIVE

Calcium phosphates are one of biomaterials that are used for bone regeneration. In this study, calcium phosphate nanoparticles such as hydroxyapatite (HA)/fluorapatite (FA),with chitosan gel filled with unrestricted somatic stem cells (USSCs) were used for healing calvarial bone in rat model.

METHODS

The healing effects of these injectable scaffolds, with and without stem cells, in bone regeneration were investigated by computed tomography (CT) analysis and pathology assays after 28 days of grafting.

RESULTS

The results of CT analysis showed that bone regeneration on the scaffolds, and the amounts of regenerated new bone for USSC scaffold were significantly greater than the scaffold without cell and untreated controls.

CONCLUSION

Therefore, the combination of scaffold especially with USSC could be considered as a useful method for bone regeneration.

Magnetic Resonance Imaging of Human Dental Pulp Stem Cells in Vitro and in Vivo

Recent advances in stem cell research have shown the promising nature of mesenchymal stem cells as plausible candidates for cell-based regenerative medicine. Many studies reported the use of human dental pulp stem cells (hDPSCs), which possess self-renewal capacity, high proliferation potential, and the ability to undergo multilineage differentiation. Together with this therapeutic approach, development of effective, noninvasive and nontoxic imaging techniques for visualizing and tracking the cells in vivo is crucial for the evaluation and improvement of stem cell therapy. Magnetic resonance imaging (MRI) is one of the most powerful diagnostic imaging techniques currently available for in vivo diagnosis and has been proposed as the most attractive modality for monitoring stem cell migration. The aim of this study was to investigate the labeling efficiency of hDPSCs using superparamagnetic iron oxide (SPIO) particles in order to allow visualization using in vitro and in vivo MRI without influencing cellular metabolism. MRI and transmission electron microscopy (TEM) showed optimal uptake with low SPIO concentrations of 15 μg/ml in combination with 0.75 μg/ml poly-l-lysine (PLL) resulting in more than 13 pg iron/cell and an in vitro detection limit of 50 labeled cells/μl. Very low SPIO concentrations in the culture medium resulted in extremely high labeling efficiency not reported before. For these conditions, tetrazolium salt assays showed no adverse effects on cell viability. Furthermore, in vivo MRI was performed to detect labeled hDPSCs transplanted into the brain of Rag 2-γ C immune-deficient mice. Transplanted cells did not show any signs of tumorgenecity or teratoma formation during the studied time course. We have reported on a labeling and imaging strategy to visualize human dental pulp stem cells in vivo using MRI. These data provide a solid base to allow cell tracking in future regenerative studies in the brain longitudinally.

Enhancement of bone formation by genetically engineered human umbilical cord-derived mesenchymal stem cells expressing osterix

OBJECTIVES

The aim of this study was to investigate if overexpression of osterix (Osx) in human umbilical cord-derived mesenchymal stem cells (UC-MSCs) would facilitate osteogenic differentiation in bone regeneration.

STUDY DESIGN

UC-MSCs were isolated from UCs. A pEGFP-Osx plasmid was constructed and applied to transfect UC-MSCs. Cell proliferation, alkaline phosphatase (ALP) activity, and expression of bone-related genes were examined to evaluate the osteogenic potential of UC-MSCs. Bone regeneration in vivo was evaluated in nude mice using PLGA as a carrier.

RESULTS

Reverse-transcription polymerase chain reaction showed that pEGFP-Osx transfection enhanced expression of bone matrix proteins. Overexpression of Osx in UC-MSCs enhanced ALP activity, while not inhibited their proliferation rate. The Osx-transduced group formed significantly more bone at 4 weeks.

CONCLUSIONS

Concerning their simple isolation and proliferation, it is believed that genetically engineered UC-MSCs could play important roles in the study and application of bone tissue engineering.

Determinants of bone marrow adiposity: the modulation of peroxisome proliferator-activated receptor-γ2 activity as a central mechanism

Although the presence of adipocytes in the bone marrow is a normal physiological phenomenon, the role of these cells in bone homeostasis and during pathological states has not yet been fully delineated. As osteoblasts and adipocytes originate from a common progenitor, with an inverse relationship existing between osteoblastogenesis and adipogenesis, bone marrow adiposity often negatively correlates with osteoblast number and bone mineral density. Bone adiposity can be affected by several physiological and pathophysiological factors, with abnormal, elevated marrow fat resulting in a pathological state. This review focuses on the regulation of bone adiposity by physiological factors, including aging, mechanical loading and growth factor expression, as well as the pathophysiological factors, including diseases such as anorexia nervosa and dyslipidemia, and pharmacological agents such as thiazolidinediones and statins. Although these factors regulate bone marrow adiposity via a plethora of different intracellular signaling pathways, these diverse pathways often converge on the modulation of the expression and/or activity of the pro-adipogenic transcription factor peroxisome proliferator-activated receptor (PPAR)-γ2, suggesting that any factor that affects PPAR-γ2 may have an impact on the fat content of bone.

Umbilical cord and bone marrow mesenchymal stem cell seeding on macroporous calcium phosphate for bone regeneration in rat cranial defects

Human umbilical cord mesenchymal stem cells (hUCMSCs) are inexhaustible and can be harvested at a low cost without an invasive procedure. However, there has been no report on comparing hUCMSCs with human bone marrow MSCs (hBMSCs) for bone regeneration in vivo. The aim of this study was to investigate hUCMSC and hBMSC seeding on macroporous calcium phosphate cement (CPC), and to compare their bone regeneration in critical-sized cranial defects in rats. Cell attachment, osteogenic differentiation and mineral synthesis on RGD-modified macroporous CPC were investigated in vitro. Scaffolds with cells were implanted in 8-mm defects of athymic rats. Bone regeneration was investigated via micro-CT and histological analysis at 4, 12, and 24 weeks. Three groups were tested: CPC with hUCMSCs, CPC with hBMSCs, and CPC control without cells. Percentage of live cells and cell density on CPC in vitro were similarly good for hUCMSCs and hBMSCs. Both cells had high osteogenic expressions of alkaline phosphatase, osteocalcin, collagen I, and Runx2. Bone mineral density and trabecular thickness in hUCMSC and hBMSC groups in vivo were greater than those of CPC control group. New bone amount for hUCMSC-CPC and hBMSC-CPC constructs was increased by 57% and 88%, respectively, while blood vessel density was increased by 15% and 20%, than CPC control group at 24 weeks. hUCMSC-CPC and hBMSC-CPC groups generally had statistically similar bone mineral density, new bone amount and vessel density. In conclusion, hUCMSCs seeded on CPC were shown to match the bone regeneration efficacy of hBMSCs in vivo for the first time. Both hUCMSC-CPC and hBMSC-CPC constructs generated much more new bone and blood vessels than CPC without cells. Macroporous RGD-grafted CPC with stem cell seeding is promising for craniofacial and orthopedic repairs.

Mesenchymal stem cells: new aspect in cell-based regenerative therapy

MSCs are multipotent progenitors which reside in bone marrow. They support hematopoietic stem cells homing, self renewal and differentiation in bone marrow. They can also differentiate into osteoblasts, adipocytes, chondrocytes, myocyates and many other tissues. In vivo, when trauma happens, MSCs operate cell renewal and migrate to the damaged tissues to regenerate that injury. In vitro, MSCs are able to proliferate and differentiate to a variety of cell lineages. This makes them a very hopeful tool for cell-based regenerative therapy for large bone defects, maxillofacial skeletal reconstruction, cardiovascular and spinal cord injury and so many other defects. The most important characteristic that make MSCs an excellent tool for cell replacement is their ability to escape from immune rejection. For therapeutic purposes they usually isolated from human bone marrow or fat and they should proliferate in order to reach an adequate number for implantation. Conventionally DMEM medium supplemented with 10% FBS is used for their expansion, but currently autologous platelet rich products are replaced FBS. Platelet granules contain so many growth factors that can support MSCs proliferation.

Effect of membrane stiffness and cytoskeletal element density on mechanical stimuli within cells: an analysis of the consequences of ageing in cells

A finite element model of a single cell was created and used to compute the biophysical stimuli generated within a cell under mechanical loading. Major cellular components were incorporated in the model: the membrane, cytoplasm, nucleus, microtubules, actin filaments, intermediate filaments, nuclear lamina and chromatin. The model used multiple sets of tensegrity structures. Viscoelastic properties were assigned to the continuum components. To corroborate the model, a simulation of atomic force microscopy indentation was performed and results showed a force/indentation simulation with the range of experimental results. A parametric analysis of both increasing membrane stiffness (thereby modelling membrane peroxidation with age) and decreasing density of cytoskeletal elements (thereby modelling reduced actin density with age) was performed. Comparing normal and aged cells under indentation predicts that aged cells have a lower membrane area subjected to high strain as compared with young cells, but the difference, surprisingly, is very small and may not be measurable experimentally. Ageing is predicted to have a more significant effect on strain deep in the nucleus. These results show that computation of biophysical stimuli within cells are achievable with single-cell computational models; correspondence between computed and measured force/displacement behaviours provides a high-level validation of the model. Regarding the effect of ageing, the models suggest only small, although possibly physiologically significant, differences in internal biophysical stimuli between normal and aged cells.

Human adipose-derived stem cells cultured in keratinocyte serum free medium: Donor's age does not affect the proliferation and differentiation capacities

BACKGROUND

Although donor age-related effects of characteristics of mesenchymal stem cells (MSC), such as a decrease in the proliferation and differentiation capacity and an increase of senescence and apoptosis, are evident, such effects are generally less prominent in adipose-derived stem cells (ASC). Using a hormone and growth factor rich medium (KFSM), this study cultured ASC from abdominal subcutaneous fat of 27 adult females in three age groups: 30-39 y, 40-49 y and 50-60 y, and investigated the growth and differentiation characteristics.

RESULTS

The derived ASC had an immunophenotype similar to that of bone marrow derived MSC (BMSC). They could be stably expanded with an average population doubling time of 21.5 ± 2.3 h. Other than a higher pre-adipogenic commitment and a lower adipogenic differentiation capability in ASC derived from the old age group, other characteristics including proliferation rate, doubling time, telomere length, as well as the osteogenic and chondrogenic differentiation capacity were the same regardless of the donor's age.

CONCLUSIONS

The study demonstrates a promising proliferation and differentiation capabilities of ASC regardless of the donor's age. The compromised adipogenic potential in the older donors could be a benefit for their application in regeneration therapy.

Mesenchymal stem cells in the treatment of pediatric diseases

BACKGROUND

In recent years, the incredible interests in mesenchymal stem cells have boosted the expectations of both patients and physicians. Unlike embryonic stem cells, neither their procurement nor their use is deemed controversial. Moreover, their immunomodulatory capacity coupled with low immunogenicity has opened up their allogenic use, consequently broadening the possibilities for their application. In May 2012, Canadian health regulators approved Prochymal, the first mesenchymal stem cells-based drug, for acute graft-versus-host diseases in children who have failed to respond to steroid treatment. The aim of this article is to review the recent advances in mesenchymal stem cells for pediatric diseases.

DATA SOURCES

A literature review was performed on PubMed from 1966 to 2013 using the MeSH terms "mesenchymal stem cells", "clinical trials" and "children". Additional articles were identified by a hand search of the references list in the initial search.

RESULTS

The following categories are described: general properties, mechanisms of action, graft-versus-host diseases, cardiovascular diseases, liver diseases, inflammatory bowel diseases, osteoarticular diseases, autoimmune diseases, type 1 diabetes, and lung diseases.

CONCLUSIONS

Mesenchymal stem cells, owing to their availability, immunomodulatory properties, low immunogenicity, and therapeutic potential, have become one of the most attractive options for the treatment of a wide range of diseases. It is expected to see more and more clinical trials and applications of mesenchymal stem cells for pediatric diseases in the near future.

Side-by-side comparison of the biological characteristics of human umbilical cord and adipose tissue-derived mesenchymal stem cells

Both human adipose tissue-derived mesenchymal stem cells (ASCs) and umbilical cord-derived mesenchymal stem cells (UC-MSCs) have been explored as attractive mesenchymal stem cells (MSCs) sources, but very few parallel comparative studies of these two cell types have been made. We designed a side-by-side comparative study by isolating MSCs from the adipose tissue and umbilical cords from mothers delivering full-term babies and thus compared the various biological aspects of ASCs and UC-MSCs derived from the same individual, in one study. Both types of cells expressed cell surface markers characteristic of MSCs. ASCs and UC-MSCs both could be efficiently induced into adipocytes, osteoblasts, and neuronal phenotypes. While there were no significant differences in their osteogenic differentiation, the adipogenesis of ASCs was more prominent and efficient than UC-MSCs. In the meanwhile, ASCs responded better to neuronal induction methods, exhibiting the higher differentiation rate in a relatively shorter time. In addition, UC-MSCs exhibited a more prominent secretion profile of cytokines than ASCs. These results indicate that although ASCs and UC-MSCs share considerable similarities in their immunological phenotype and pluripotentiality, certain biological differences do exist, which might have different implications for future cell-based therapy.

Histone deacetylation mediates the rejuvenation of osteoblastogenesis by the combination of 25(OH)D3 and parathyroid hormone in MSCs from elders

Vitamin D metabolites are important effectors of bone and mineral homeostasis. Human bone marrow stromal cells (hMSCs) are targets of 1α,25-dihydroxyvitamin D [1α,25(OH)2D] action to promote their differentiation to osteoblasts. Osteoblastogenesis is also stimulated by 25-hydroxyvitamin D [25(OH)D], an effect that requires conversion to 1α,25(OH)2D3 by 25-hydroxyvitamin D3 1α-hydroxylase (CYP27B1). These findings support an autocrine/paracrine role of vitamin D metabolism in osteoblastogenesis of hMSCs. In this study, we assessed whether and by what mechanisms osteoblastogenesis could be rejuvenated with hMSCs from elders. First, knockdown studies with VDR-siRNA showed that both the pro-differentiation and anti-proliferative effects of 1α,25(OH)2D3 required VDR. Second, 100nM 25(OH)D3 (p<0.01 vs. control, ANOVA) and 100nM PTH1-34 (p<0.05) significantly stimulated alkaline phosphatase (ALP) activity (a measure of osteoblastogenesis), with a synergistic effect when combined (p<0.001). Scriptaid, an inhibitor of histone deacetylase, blocked the effect of 25(OH)D3 and PTH on osteoblastogenesis. Scriptaid alone downregulated VDR in hMSCs. These data demonstrate that histone deacetylation is required for the synergistic effect of 25(OH)D3 and PTH on osteoblastogenesis in hMSCs. Both VDR siRNA and Scriptaid dowregulated VDR mRNA and inhibited osteoblastogenesis. Thus, epigenetic regulation of the VDR may be central to rejuvenating osteoblastogenesis in hMSCs from elders. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Isolation and characterization of multipotent cells from human fetal dermis

We report that cells from human fetal dermis, termed here multipotent fetal dermal cells, can be isolated with high efficiency by using a nonenzymatic, cell outgrowth method. The resulting cell population was consistent with the definition of mesenchymal stromal cells by the International Society for Cellular Therapy. As multipotent fetal dermal cells proliferate extensively, with no loss of multilineage differentiation potential up to passage 25, they may be an ideal source for cell therapy to repair damaged tissues and organs. Multipotent fetal dermal cells were not recognized as targets by T lymphocytes in vitro, thus supporting their feasibility for allogenic transplantation. Moreover, the expansion protocol did not affect the normal phenotype and karyotype of cells. When compared with adult dermal cells, fetal cells displayed several advantages, including a greater cellular yield after isolation, the ability to proliferate longer, and the retention of differentiation potential. Interestingly, multipotent fetal dermal cells expressed the pluripotency marker SSEA4 (90.56 ± 3.15% fetal vs. 10.5 ± 8.5% adult) and coexpressed mesenchymal and epithelial markers (>80% CD90(+)/CK18(+) cells), coexpression lacking in the adult counterparts isolated under the same conditions. Multipotent fetal dermal cells were able to form capillary structures, as well as differentiate into a simple epithelium in vitro, indicating skin regeneration capabilities.

Vitamin D metabolism in human bone marrow stromal (mesenchymal stem) cells

There are many human extra-renal tissues and cells that biosynthesize 1α,25-dihydroxyvitamin D (1α,25(OH)(2)D) by the action of CYP27B1/1α-hydroxylase. Human marrow stromal cells (hMSCs), also known as mesenchymal stem cells, were isolated from marrow discarded from well-characterized, consented subjects during common orthopedic procedures. Human MSCs can give rise to osteoblasts, chondrocytes, adipocytes, and other lineages. Their in vitro differentiation to osteoblasts is stimulated by 1α,25(OH)(2)D, and recent evidence indicates that they have the capacity to metabolize vitamin D in a regulated manner. Human MSCs express the vitamin D receptor, 25-hydroxylases, 1α-hydroxylase, and 24-hydroxylase; stimulation of in vitro osteoblastogenesis by 25(OH)D depends on the activity of CYP27B1/1α-hydroxylase. The finding that hMSCs are a both a producer and target of 1α,25(OH)(2)D suggests a potential autocrine/paracrine role of vitamin D metabolism in osteoblast differentiation. Expression and enzyme activity of CYP27B1/1α-hydroxylase are upregulated by substrate 25(OH)D and Parathyroid Hormone (PTH) and are downregulated by 1α,25(OH)(2)D. With subject age, there are decreases in basal osteoblast potential and in stimulation of osteoblastogenesis by 1α,25(OH)(2)D, 25(OH)D, and PTH. In vitro treatment with a combination of 25(OH)D and PTH rejuvenated osteoblastogenesis with hMSCs from elders; this was attributable to increases in CYP27B1/1α-hydroxylase and in receptor for each hormone by the reciprocal factor. Other clinical variables beside age, i.e. low serum 25(OH)D or low estimated glomerular filtration rate, are correlated with reduced osteoblastogenesis. These studies suggest that osteoblastogenesis may not be optimal unless there is sufficient serum 25(OH)D substrate for hMSCs to synthesize and respond to local 1α,25(OH)(2)D.

Human mesenchymal stem cells: a bank perspective on the isolation, characterization and potential of alternative sources for the regeneration of musculoskeletal tissues

The continuous discovery of human mesenchymal stem cells (hMSCs) in different tissues is stirring up a tremendous interest as a cell source for regenerative medicine therapies. Historically, hMSCs have been always considered a sub-population of mononuclear cells present in the bone marrow (BM). Although BM-hMSCs are still nowadays considered as the most promising mesenchymal stem cell population to reach the clinics due to their capacity to differentiate into multiple tissues, hMSCs derived from other adult and fetal tissues have also demonstrated to possess similar differentiation capacities. Furthermore, different reports have highlighted a higher recurrence of hMSCs in some of these tissues as compared to BM. This offer a fascinating panorama for cell banking, since the creation of a stem cell factory could be envisioned where hMSCs are stocked and used for ad hoc clinical applications. In this review, we summarize the main findings and state of the art in hMSCs isolation, characterization, and differentiation from alternative tissue sources and we attempt to compare their potency for musculoskeletal regeneration.

Cell sources for trachea tissue engineering: past, present and future

Trachea tissue engineering has been one of the most promising approaches to providing a potential clinical application for the treatment of long-segment tracheal stenosis. The sources of the cells are particularly important as the primary factor for tissue engineering. The use of appropriate cells seeded onto scaffolds holds huge promise as a means of engineering the trachea. Furthermore, appropriate cells would accelerate the regeneration of the tissue even without scaffolds. Besides autologous mature cells, various stem cells, including bone marrow-derived mesenchymal stem cells, adipose tissue-derived stem cells, umbilical cord blood-derived mesenchymal stem cells, amniotic fluid stem cells, embryonic stem cells and induced pluripotent stem cells, have received extensive attention in the field of trachea tissue engineering. Therefore, this article reviews the progress on different cell sources for engineering tracheal cartilage and epithelium, which can lead to a better selection and strategy for engineering the trachea.

A generic micropatterning platform to direct human mesenchymal stem cells from different origins towards myogenic differentiation

Human mesenchymal stem cells (MSCs) derived from various origins show varied differentiation capability. Recent work shows that cell shape manipulation via micropatterning can modulate the differentiation of bone-marrow-derived MSCs. Herein, the effect of micropatterning on the myogenesis of MSCs isolated from three different sources (bone marrow, fetal tissue, and adipose) is reported. All the well-aligned cells, regardless of source, predominantly commit to myogenic lineage, as shown by the significant upregulation of myogenic gene markers and positive myosin heavy chain staining. It is demonstrated that our novel micropattern can be used as a generic platform for inducing myogenesis of MSCs from different sources and may also have the potential to be extended to induce other lineage commitment.

Comparison of the neural differentiation potential of human mesenchymal stem cells from amniotic fluid and adult bone marrow

Human mesenchymal stem cells (MSCs) are considered a promising tool for cell-based therapies of nervous system diseases. Bone marrow (BM) has been the traditional source of MSCs (BM-MSCs). However, there are some limitations for their clinical use, such as the decline in cell number and differentiation potential with age. Recently, amniotic fluid (AF)-derived MSCs (AF-MSCs) have been shown to express embryonic and adult stem cell markers, and can differentiate into cells of all three germ layers. In this study, we isolated AF-MSCs from second-trimester AF by limiting dilution and compared their proliferative capacity, multipotency, neural differentiation ability, and secretion of neurotrophins to those of BM-MSCs. AF-MSCs showed a higher proliferative capacity and more rapidly formed and expanded neurospheres compared to those of BM-MSCs. Both immunocytochemical and quantitative real-time PCR analyses demonstrated that AF-MSCs showed higher expression of neural stemness markers than those of BM-MSCs following neural stem cell (NSC) differentiation. Furthermore, the levels of brain-derived growth factor and nerve growth factor secreted by AF-MSCs in the culture medium were higher than those of BM-MSCs. In addition, AF-MSCs maintained a normal karyotype in long-term cultures after NSC differentiation and were not tumorigenic in vivo. Our findings suggest that AF-MSCs are a promising and safe alternative to BM-MSCs for therapy of nervous system diseases.

Efeito in vitro da triiodotironina sob o potencial osteogênico reduzido de células-tronco mesenquimais do tecido adiposo de ratas ovariectomizadas e com osteoporose

OBJETIVO: Avaliar se a triiodotironina (T3) aumenta a diferenciação osteogênica das células-tronco mesenquimais do tecido adiposo (CTM-TA) de ratas adultas ovariectomizadas e com osteoporose e compará-lo ao de ratas adultas e jovens sem osteoporose. MATERIAIS E MÉTODOS: CTM-TA foram cultivadas em meio osteogênico e distribuídas em sete grupos: 1) CTM-TA de ratas jovens sem osteoporose; 2) CTM-TA de ratas adultas sem osteoporose; 3) CTM-TA de ratas adultas com osteoporose e 4, 5, 6 e 7) CTM-TA de ratas adultas com osteoporose tratadas com T3 (0,01 nM, 1 nM, 100 nM e 1.000 nM). AVALIARAM-SE: atividade da fosfatase alcalina, conversão do dimetiltiazol (MTT), porcentagem de nódulos de mineralização, celularidade e quantificação de transcriptos gênicos para colágeno I, osteocalcina, osteopontina e Bmp-2. RESULTADOS: Independente da dose, T3 reduziu a conversão do MTT, a atividade da fosfatase, a porcentagem de células e a expressão de colágeno I em pelo menos uma das doses e dos períodos estudados (p < 0,05). Mas o tratamento com T3 não alterou o número de nódulos de mineralização e a expressão de osteopontina e Bmp-2 em culturas de CTM-TA de ratas adultas com osteoporose (p > 0,05). CONCLUSÃO: T3 apresenta efeitos negativos sobre alguns fatores envolvidos na diferenciação osteogênica de CTM-TA, sem, no entanto, reduzir a formação de nódulos de mineralização e a expressão de proteínas ósseas.

Advanced Strategies for Articular Cartilage Defect Repair

Articular cartilage is a unique tissue owing to its ability to withstand repetitive compressive stress throughout an individual's lifetime. However, its major limitation is the inability to heal even the most minor injuries. There still remains an inherent lack of strategies that stimulate hyaline-like articular cartilage growth with appropriate functional properties. Recent scientific advances in tissue engineering have made significant steps towards development of constructs for articular cartilage repair. In particular, research has shown the potential of biomaterial physico-chemical properties significantly influencing the proliferation, differentiation and matrix deposition by progenitor cells. Accordingly, this highlights the potential of using such properties to direct the lineage towards which such cells follow. Moreover, the use of soluble growth factors to enhance the bioactivity and regenerative capacity of biomaterials has recently been adopted by researchers in the field of tissue engineering. In addition, gene therapy is a growing area that has found noteworthy use in tissue engineering partly due to the potential to overcome some drawbacks associated with current growth factor delivery systems. In this context, such advanced strategies in biomaterial science, cell-based and growth factor-based therapies that have been employed in the restoration and repair of damaged articular cartilage will be the focus of this review article.

Mesenchymal autologous stem cells

The use of cell-based therapies for spinal cord injuries has recently gained prominence as a potential therapy or component of a combination strategy. Experimental and clinical studies have been performed using mesenchymal stem cell therapy to treat spinal cord injuries with encouraging results. However, there have been reports on the adverse effects of these stem cell-based therapies, especially in the context of tumor modulation. This article surveys the literature relevant to the potential of mesenchymal autologous stem cells for spinal cord injuries and their clinical implications.

Transplantation-potential-related biological properties of decidua basalis mesenchymal stem cells from maternal human term placenta

Human placental decidua basalis originates from the maternal side of the placenta and has been described as a source of mesenchymal stem cells (MSCs). However, for its application in tissue regeneration and repair, the transplantation-potential-related biological properties of decidua-basalis-derived mesenchymal stem cells (DBMSCs) remain to be elucidated. We obtained DBMSCs through enzymatic digestion and density gradient centrifugation and confirmed their capacity to differentiate into cell types of the mesodermal lineage, such as osteoblasts, adipocytes and chondroblasts. Karyotype analysis showed that the isolated DBMSCs maintained chromosomal stability after long-term culture in vitro. Growth kinetics and ultrastructural observation revealed a high level of DBMSC proliferative activity. In addition, DBMSCs showed immunosuppressive properties by suppressing both mitogen- and alloantigen-induced peripheral lymphocyte proliferation. All of these properties suggest that DBMSCs, which are abundant and easily accessible, are a novel potential source of seed cells for cell transplantation treatments.

Triiodotironina não aumenta a diferenciação osteogênica reduzida pela idade de células-tronco mesenquimais da medula óssea de ratas

OBJETIVO: Avaliar se a adição de T3 aumenta o potencial osteogênico das células-tronco mesenquimais da medula óssea (CTM-MO) de ratas adultas normais comparado ao de ratas jovens. MATERIAIS E MÉTODOS: CTM-MO foram cultivadas em meio osteogênico e separadas em seis grupos: 1) CTM-MO de ratas jovens; 2) CTM-MO de ratas adultas; 3, 4, 5 e 6) CTM-MO de ratas adultas com T3 nas concentrações de 0,01; 1; 100 e 1000 nM, respectivamente. Foram avaliados: atividade da fosfatase alcalina, conversão do dimetiltiazol (MTT) e síntese de colágeno aos sete, 14 e 21 dias e celularidade e número de nódulos de mineralização aos 21 dias de diferenciação. RESULTADOS: T3 reduziu significativamente a conversão do MTT, a atividade da fosfatase alcalina, a síntese de colágeno e a formação dos nódulos de mineralização em pelo menos uma das doses e dos períodos estudados (p < 0,05). Os valores foram menores quando comparados aos das CTM-MO de ratas jovens e adultas sem T3 (p < 0,05). CONCLUSÃO: T3 apresenta efeitos negativos sobre os fatores envolvidos na diferenciação osteogênica das CTM-MO de ratas adultas.

Human embryonic stem cell-derived mesenchymal stem cell seeding on calcium phosphate cement-chitosan-RGD scaffold for bone repair

Calcium phosphate cement (CPC) has in situ-setting ability and excellent osteoconductivity. Human embryonic stem cells (hESCs) are exciting for regenerative medicine due to their strong proliferative ability and multilineage differentiation capability. However, there has been no report on hESC seeding with CPC. The objectives of this study were to obtain hESC-derived mesenchymal stem cells (hESCd-MSCs), and to investigate hESCd-MSC proliferation and osteogenic differentiation on novel CPC with chitosan immobilized with RGD (CPC-chitosan-RGD). RGD was covalently bonded with chitosan, which was then incorporated into CPC. The CPC-chitosan-RGD scaffold had higher strength and toughness than CPC-chitosan control without RGD (p<0.05). hESCs were cultured to form embryoid bodies (EBs), and the MSCs were then migrated out of the EBs. Flow cytometry indicated that the hESCd-MSCs expressed typical surface antigen profile of MSCs. hESCd-MSCs had good viability when seeded on CPC scaffolds. The percentage of live cells and the cell density were significantly higher on CPC-chitosan-RGD than CPC-chitosan control. Scanning electron microscope examination showed hESCd-MSCs with a healthy spreading morphology adherent to CPC. hESCd-MSCs expressed high levels of osteogenic markers, including alkaline phosphatase, osteocalcin, collagen I, and Runx2. The mineral synthesis by the hESCd-MSCs on the CPC-chitosan-RGD scaffold was twice that for CPC-chitosan control. In conclusion, hESCs were successfully seeded on CPC scaffolds for bone tissue engineering. The hESCd-MSCs had good viability and osteogenic differentiation on the novel CPC-chitosan-RGD scaffold. RGD incorporation improved the strength and toughness of CPC, and greatly enhanced the hESCd-MSC attachment, proliferation, and bone mineral synthesis. Therefore, the hESCd-MSC-seeded CPC-chitosan-RGD construct is promising to improve bone regeneration in orthopedic and craniofacial applications.

Mesenchymal stem cells and their use in therapy: what has been achieved?

The considerable therapeutic potential of human multipotent mesenchymal stromal cells or mesenchymal stem cells (MSCs) has generated increasing interest in a wide variety of biomedical disciplines. Nevertheless, researchers report studies on MSCs using different methods of isolation and expansion, as well as different approaches to characterize them; therefore, it is increasingly difficult to compare and contrast study outcomes. To begin to address this issue, the Mesenchymal and Tissue Stem Cell Committee of the International Society for Cellular Therapy proposed minimal criteria to define human MSCs. First, MSCs must be plastic-adherent when maintained in standard culture conditions (α minimal essential medium plus 20% fetal bovine serum). Second, MSCs must express CD105, CD73 and CD90, and MSCs must lack expression of CD45, CD34, CD14 or CD11b, CD79α or CD19 and HLA-DR surface molecules. Third, MSCs must differentiate into osteoblasts, adipocytes and chondroblasts in vitro. MSCs are isolated from many adult tissues, in particular from bone marrow and adipose tissue. Along with their capacity to differentiate and transdifferentiate into cells of different lineages, these cells have also generated great interest for their ability to display immunomodulatory capacities. Indeed, a major breakthrough was the finding that MSCs are able to induce peripheral tolerance, suggesting that they may be used as therapeutic tools in immune-mediated disorders. Although no significant adverse events have been reported in clinical trials to date, all interventional therapies have some inherent risks. Potential risks for undesirable events, such as tumor development, that might occur while using these stem cells for therapy must be taken into account and contrasted against the potential benefits to patients.

Live-cell, temporal gene expression analysis of osteogenic differentiation in adipose-derived stem cells

Adipose-derived stem cells (ASCs) are a widely investigated type of mesenchymal stem cell with great potential for musculoskeletal regeneration. However, use of ASCs is complicated by their cellular heterogeneity, which exists at both the population and single-cell levels. This study demonstrates a live-cell assay to investigate gene expression in ASCs undergoing osteogenesis using fluorescently tagged DNA hybridization probes called molecular beacons. Three molecular beacons were designed to target mRNA sequences for alkaline phosphatase, type I collagen, and osteocalcin (ALPL, COL1A1, and BGLAP), genes characteristically expressed during osteogenesis. The percentage of cells expressing these genes in a population was monitored daily to quantify the uniformity of the differentiation process. Differentiating ASC populations were repeatedly measured in a nondestructive fashion over a 21-day period to obtain temporal gene expression data. Results showed consistent expression patterns for the investigated osteogenic genes in response to induction medium. Peak expression was observed at days 3-4 for ALPL, day 14 for COL1A1, and day 21 for BGLAP. Additionally, the differentiation response of sample populations became more uniform after 2 weeks in osteogenic induction medium, suggesting a syncing of ASCs occurs over time. These findings are consistent with previous studies of osteogenic differentiation and suggest that molecular beacons are a viable means to monitor the spatiotemporal gene expression of live, differentiating ASCs.

Unique molecular signatures influencing the biological function and fate of post-natal stem cells isolated from different sources

The discovery of mesenchymal stem cells (MSCs) from a myriad of tissues has triggered the initiative of establishing tailor-made stem cells for disease-specific therapy. Nevertheless, lack of understanding on the inherent differential propensities of these cells may restrict their clinical outcome. Therefore, a comprehensive study was done to compare the proliferation, differentiation, expression of cell surface markers and gene profiling of stem cells isolated from different sources, viz. bone marrow, Wharton's jelly, adipose tissue and dental pulp. We found that although all MSCs were phenotypically similar to each other, Wharton's jelly (WJ) MSCs and dental pulp stem cells (DPSCs) were highly proliferative as compared to bone marrow (BM) MSCs and adipose tissue (AD) MSCs. Moreover, indistinguishable cell surface characteristics and differentiation capacity were confirmed to be similar among all cell types. Based on gene expression profiling, we postulate that BM-MSCs constitutively expressed genes related to inflammation and immunodulation, whereas genes implicated in tissue development were highly expressed in AD-MSCs. Furthermore, the transcriptome profiling of WJ-MSCs and DPSCs revealed an inherent bias towards the neuro-ectoderm lineage. Based on our findings, we believe that there is no unique master mesenchymal stem cell that is appropriate to treat all target diseases. More precisely, MSCs from different sources exhibit distinct and unique gene expression signatures that make them competent to give rise to specific lineages rather than others. Therefore, stem cells should be subjected to rigorous characterization and utmost vigilance needs to be adopted in order to choose the best cellular source for a particular disease.

Surface markers for chondrogenic determination: a highlight of synovium-derived stem cells

Cartilage tissue engineering is a promising field in regenerative medicine that can provide substantial relief to people suffering from degenerative cartilage disease. Current research shows the greatest chondrogenic potential for healthy articular cartilage growth with minimal hypertrophic differentiation to be from mesenchymal stem cells (MSCs) of synovial origin. These stem cells have the capacity for differentiation into multiple cell lineages related to mesenchymal tissue; however, evidence exists for cell surface markers that specify a greater potential for chondrogenesis than other differentiation fates. This review will examine relevant literature to summarize the chondrogenic differentiation capacities of tested synovium-derived stem cell (SDSC) surface markers, along with a discussion about various other markers that may hold potential, yet require further investigation. With this information, a potential clinical benefit exists to develop a screening system for SDSCs that will produce the healthiest articular cartilage possible.

In vitro differentiation of osteocytes and adipocytes from human placenta-derived cells

OBJECTIVE

To investigate the capability of human placenta-derived adherent cells to differentiate into osteocytes and adipocytes.

METHODS

Placenta-derived adherent cells were isolated by type IV collagenase digestion of a single freshly obtained human placenta and cultured under standard conditions. Cell surface markers of adherent cells from passages 3 - 9 were analysed by flow cytometry. Osteocytic differentiation was induced with β-glycerol phosphate, vitamin C and dexamethasone and confirmed by Alizarin red staining. Adipocytic differentiation was induced with dexamethasone and insulin and confirmed by oil red O staining.

RESULTS

Placenta-derived adherent cells were positive for high levels of CD44 and CD105 and very low levels of CD29 but were negative for CD34, CD45 and CD19. This pattern of cell surface markers is identical to human mesenchymal stem cells. Alizarin red-positive cells were detected 10 days after the induction of osteocyte differentiation. Oil red O-positive cells were detected 7 days after the induction of adipocyte differentiation.

CONCLUSIONS

Placenta-derived adherent cells can differentiate into either osteocytes or adipocytes in vitro. The human placenta may provide an alternative source of mesenchymal stem cells for basic research and clinical use.

An animal model study for repair of tracheal defects with autologous stem cells and differentiated chondrocytes from adipose-derived stem cells

BACKGROUND

Stenosis of trachea with mucosal and cartilage lesions is a challenging problem in tracheal surgery. Owing to ease of harvest and abundance, adipose-derived stem cells (ADSCs) are attractive and increasingly used in tissue engineering. The aim of this study was to evaluate the repair of trachea with autologous stem cells and differentiated chondrocytes from adipose-derived stem cells in an animal model.

METHODS AND MATERIAL

Six canine ADSCs were isolated and proliferated in monolayer culture and CD44; CD90 markers were investigated by flow cytometry. ADSCs were seeded in alginate beads and were differentiated into chondrocytes by TGF-β3. Cartilage-specific markers with reverse transcriptase polymerase chain reaction were demonstrated in differentiated cells. These differentiated cells and stem cells in alginate scaffold were separately transferred to a defect created in canine's trachea. After 8 weeks, the healing and cartilage formation in the trachea was evaluated by histological methods.

RESULTS

We identified formed cartilage pieces and chondrocytes with lacuna and extracellular matrix in defects implanted with differentiated cells, but in other groups, staining of the sections did not show the presence of cartilage in the engineered tracheal wall.

CONCLUSION

We showed that cartilage- engineered from differentiated adipose-derived stem cells in alginate biodegradable scaffold could repair tracheal cartilage defects.

Repair and Regeneration of Skin Injury by Transplanting Microparticles Mixed With Wharton’s Jelly and MSCs From the Human Umbilical Cord

The prognosis for extensive and deep skin injury is not satisfactory because of scar formation and the loss of normal function and skin appendages. Several novel therapies for skin repair and regeneration have emerged. Currently, stem cell–based therapies are attractive candidates in regenerative medicine to treat skin injuries. Human umbilical cord Wharton’s jelly–derived mesenchymal stem cells (hUC-MSCs) have become a unique, accessible, and noncontroversial source of regeneration in medicine. The aim of this study was to explore a new strategy for treating skin wounds. A mixture of hUC-MSCs, Wharton’s jelly, and skin microparticles were transplanted to 10-mm diameter, full-thickness, middorsal, excisional skin wounds of mice. After 7 days, the tissue sections were sampled for reconstruction analysis and histological examination. After transplantation, there was a remarkable development of newborn skin and its appendages. We could see newly generated layers of epidermis, sebaceous glands, hair follicle, and sweat glands clearly. This innovative strategy could be very promising and may significantly increase the quality of repair and regeneration of skin in injuries.

Comparative transcriptome analysis reveals a fetal origin for mesenchymal stem cells and novel fetal surface antigens for noninvasive prenatal diagnosis

OBJECTIVE

Mesenchymal stem cells (MSCs) are an attractive source for providing the cells necessary for regenerating damaged tissues. Fetal MSCs (fMSCs) are known to proliferate fast and have an excellent osteogenic capacity, yet the underlying mechanisms need to be explored. A better understanding of MSCs from different anatomic origins and ages will eventually benefit cell-based therapies, as well as subsequent mechanistic studies in the field of stem cell biology.

MATERIALS AND METHODS

We identified the molecular signatures of fetal and adult MSCs via a meta-analytic strategy and compared the enriched canonical pathways and genetic networks within each signature.

RESULTS

Fetal MSCs were found to express more cell cycle genes, which is consistent with the results of wetlab functional assays. In addition, the genes involved in vasculogenesis, neurogenesis, Wnt, MAPKKK pathways, and RNA splicing were found to be enriched in fMSCs. Correlating with the overexpression of multilineage differentiation genes, fMSCs share more genes with embryonic stem cells (ESCs) and are, therefore, more primitive. Further exploration into the transcriptome similarities revealed that MSCs from umbilical cord blood (UCB) express dominant fMSC genes, but not adult genes, suggesting a fetal origin for UCB MSCs. Novel surface proteins that were dominantly expressed in fetal and UCB MSCs, but not in adult MSCs or maternal PBMCs, were also identified.

CONCLUSION

Our results systematically revealed the underlying genes and regulatory networks of two MSCs from unique origins, the resulting phenotypes, as well as the origin of UCB MSCs. The novel membrane proteins on the fetal MSC surface are promising candidate biomarkers for positively isolating fetal MSCs from maternal blood for noninvasive prenatal diagnosis.

Human placental decidua basalis-derived mesenchymal stem cells differentiate into dopamine neuron-like cells with no response to long-term culture in vitro

Human placental decidua basalis-derived mesenchymal stem cells (DBMSCs) have been identified as valuable sources for cell transplantation. In this study, we found that DBMSCs could be induced to form neural stem cells in the form of neurospheres. These neurospheres were further differentiated into dopamine neuron-like cells with a cocktail of cytokines. The differentiated DBMSCs were verified through the presence of a neuron-like morphology, the expression of specific dopamine neuron makers, and the production of dopamine. In addition, this differentiation capacity of DBMSCs was not affected by long-term culture, and the cells maintained a normal karyotype in vitro. The dopamine neuronal differentiation and the relative safety transplantation potential of DBMSCs may facilitate stem cell therapeutic approaches to Parkinson's disease.

Efficacy and safety of human adipose tissue-derived mesenchymal stem cells for supporting hematopoiesis

We have demonstrated that adipose tissue-derived mesenchymal stem cells (ADSCs) from mice are capable of reconstituting the hematopoietic microenvironment, and facilitate hematopoiesis more effectively than bone marrow-derived mesenchymal stem cells (BMSCs) in mouse. The ready accessibility of fat tissue rich in MSCs and the higher hematopoiesis-supporting capacities of ADSCs suggest that ADSCs might represent a new therapeutic modality for the regeneration of impaired hematopoiesis. As a further step towards their use in clinical practice, we established human BMSCs and ADSCs from healthy volunteers of similar age, and compared their proliferation capacities, hematopoiesis-supporting properties, and safety. In vitro cell proliferation studies revealed that ADSCs have a higher population doubling number than BMSCs. In vitro co-culture assays showed that ADSCs not only support human CD34(+) peripheral blood stem cells (PBSCs), but also yield significantly more non-adherent hematic cells than BMSCs. In vitro progenitor assays revealed that ADSCs promote a higher frequency of early progenitors than do BMSCs. Interestingly, BM cellularity in irradiated mice that had received ADSCs tended to be higher than that of mice treated with BMSCs. When MSCs were injected into the BM cavity of tibiae, we observed no evidence of MSC-induced toxicity either during or after treatment. In addition, no microscopic abnormalities were observed in the bone marrow and major organs.

Human embryonic stem cell encapsulation in alginate microbeads in macroporous calcium phosphate cement for bone tissue engineering

Human embryonic stem cells (hESC) are promising for use in regenerative medicine applications because of their strong proliferative ability and multilineage differentiation capability. To date there have been no reports on hESC seeding with calcium phosphate cement (CPC). The objective of this study was to investigate hESC-derived mesenchymal stem cell (hESCd-MSC) encapsulation in hydrogel microbeads in macroporous CPC for bone tissue engineering. hESC were cultured to form embryoid bodies (EB), and the MSC were then migrated out of the EB. hESCd-MSC had surface markers characteristic of MSC, with positive alkaline phosphatase (ALP) staining when cultured in osteogenic medium. hESCd-MSC were encapsulated in alginate at a density of 1millioncellsml(-1), with an average microbead size of 207μm. CPC contained mannitol porogen to create a porosity of 64% and 218-μm macropores, with 20% absorbable fibers for additional porosity when the fibers degrade. hESCd-MSC encapsulated in microbeads in CPC had good viability from 1 to 21days. ALP gene expression at 21days was 25-fold that at 1day. Osteocalcin (OC) at 21days was two orders of magnitude of that at 1day. ALP activity in colorimetric p-nitrophenyl phosphate assay at 21days was fivefold that at 1day. Mineral synthesis by the encapsulated hESCd-MSC at 21days was sevenfold that at 1day. Potential benefits of the CPC-stem cell paste include injectability, intimate adaptation to complex-shaped bone defects, ease in contouring to achieve esthetics in maxillofacial repairs, and in situ setting ability. In conclusion, hESCd-MSC were encapsulated in alginate microbeads in macroporous CPC, showing good cell viability, osteogenic differentiation and mineral synthesis for the first time. The hESCd-MSC-encapsulating macroporous CPC construct is promising for bone regeneration in a wide range of orthopedic and maxillofacial applications.

Clinical characteristics influence in vitro action of 1,25-dihydroxyvitamin D(3) in human marrow stromal cells

Vitamin D is important for bone health, with low vitamin D levels being associated with skeletal fragility and fractures. Among its other biological activities, 1,25-dihydroxyvitamin D (1,25(OH)(2) D), stimulates the in vitro differentiation of human marrow stromal cells (hMSCs) to osteoblasts, which can be monitored by increases in alkaline phosphatase enzyme activity or osteocalcin gene expression. In this study, we tested the hypotheses that age and clinical attributes of subjects influence in vitro responsiveness of hMSCs to 1,25(OH)(2) D(3) . In a cohort of subjects whose hMSCs were isolated from bone marrow discarded during hip replacement surgery for osteoarthritis, there were significant inverse correlations with age for bone mineral density, renal function, body mass index, fat mass index, and lean mass index (n = 36-53). There were significant correlations with serum 25(OH)D for serum parathyroid hormone (PTH), body mass index, fat mass index, and lean mass index (n = 47-50). In vivo-in vitro correlation analyses indicated that there were significantly greater in vitro effects of 1,25(OH)(2) D(3) to stimulate osteoblast differentiation in hMSCs obtained from subjects who were younger than 65 years of age, or who had serum 25(OH)D ≤ 20 ng/mL, elevated serum PTH, or better renal function, assessed by estimated glomerular filtration rate. The greater in vitro stimulation of osteoblast differentiation by 1,25(OH)(2) D(3) in hMSCs from vitamin D-deficient subjects suggests that vitamin D replenishment may lead to more vigorous bone formation in subjects at risk.

Superior osteogenic capacity of different mesenchymal stem cells for bone tissue engineering

OBJECTIVE

We evaluated the effect of human bone marrow stromal cells (hBMSCs), human adipose tissue-derived mesenchymal stem cells (hAD-MSCs), and umbilical cord-derived mesenchymal stem cells (hUC-MSCs) in bone tissue engineering and identified a reliable cell source.

STUDY DESIGN

Alkaline phosphatase (ALP) activity and quantitative polymerase chain reaction were used to evaluate osteogenic in vitro, X-ray and histologic analysis in vivo.

RESULTS

hBMSCs exhibited strongest ALP staining, followed by hAD-MSCs and hUC-MSCs. At 7 days, hUC-MSCs and hAD-MSCs had higher expression of collagen type I and Runt-related transcription factor 2 than hBMSCs, and hUC-MSCs showed higher osteopontin expression. Bone structure was observed in the hUC-MSC group. Defects showed good healing in the hBMSC and hAD-MSC groups. Enhanced green fluorescent protein and osteopontin were detected in newly formed bone at 8 weeks.

CONCLUSIONS

Our results suggested that hUC-MSCs and hAD-MSCs could be used for bone tissue engineering effectively; hUC-MSCs could serve as a new alternative cell source.

Stem cells in dentistry--part I: stem cell sources

Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral and maxillofacial tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (iPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. Part I of this review outlines various types of intra- and extra-oral tissue-derived stem cells with regard to clinical availability and applications in dentistry. Additionally, appropriate sources of stem cells for regenerative dentistry are discussed with regard to differentiation capacity, accessibility and possible immunomodulatory properties.

Proliferation and differentiation potential of human adipose-derived mesenchymal stem cells isolated from elderly patients with osteoporotic fractures

Aging has less effect on adipose-derived mesenchymal stem cells (ADSCs) than on bone marrow-derived mesenchymal stem cells (BMSCs), but whether the fact holds true in stem cells from elderly patients with osteoporotic fractures is unknown. In this study, ADSCs and BMSCs of the same donor were harvested and divided into two age groups. Group A consisted of 14 young patients (36.4 ± 11.8 years old), and group B consisted of eight elderly patients (71.4 ± 3.6 years old) with osteoporotic fractures. We found that the doubling time of ADSCs from both age groups was maintained below 70 hrs, while that of BMSCs increased significantly with the number of passage. When ADSCs and BMSCs from the same patient were compared, there was a significant increase in the doubling time of BMSCs in each individual from passages 3 to 6. On osteogenic induction, the level of matrix mineralization of ADSCs from group B was comparable to that of ADSCs from group A, whereas BMSCs from group B produced least amount of mineral deposits and had a lower expression level of osteogenic genes. The p21 gene expression and senescence-associated β-galactosidase activity were lower in ADSCs compared to BMSCs, which may be partly responsible for the greater proliferation and differentiation potential of ADSCs. It is concluded that the proliferation and osteogenic differentiation of ADSCs were less affected by age and multiple passage than BMSCs, suggesting that ADSCs may become a potentially effective therapeutic option for cell-based therapy, especially in elderly patients with osteoporosis.