Viable Mesenchymal Stem Cells Research Articles

In Vivo Magnetic Resonance Imaging and Optical Imaging Comparison of Viable and Nonviable Mesenchymal Stem Cells with a Bifunctional Label

The purpose of this study was to compare viable and nonviable bilabeled mesenchymal stem cells (MSCs) in arthritic joints with magnetic resonance imaging (MRI) and optical imaging (OI). MSCs were labeled with ferucarbotran and DiD. MRI and OI of bilabeled cells were compared with controls. Six rats with arthritis received intra-articular injections of bilabeled viable MSCs into the right knee and nonviable MSCs into the left knee. Animals underwent MRI and OI preinjection and at 4, 24, 48, and 72 hours postinjection. The results were analyzed with a mixed random effects model and Fisher probability. Bilabeled MSCs showed increased MRI and OI signals compared to unlabeled controls (p < .0001). After intra-articular injection, bilabeled MSCs caused significant T2 and T2* effect on MRI and fluorescence on OI up to 72 hours postinjection (p < .05). There was no significant difference between viable and nonviable MSC signal in the knee joints; however, some of the viable cells migrated to an adjacent inflamed ankle joint (p < .05). Immunohistochemistry confirmed viable MSCs in right knee and ankle joints and nonviable MSCs in the left knee. Viable and nonviable cells could not be differentiated with MRI or OI signal intensity but were differentiated based on their ability to migrate in vivo.

Fabrication of porous polysaccharide-based scaffolds using a combined freeze-drying/cross-linking process

Biocompatible three-dimensional (3-D) porous scaffolds are of great interest for tissue engineering applications. We here present a novel combined freeze-drying/cross-linking process to prepare porous polysaccharide-based scaffolds. This process does not require an organic solvent or porogen agent. We unexpectedly found that cross-linking of biomacromolecules such as pullulan and dextran with sodium trimetaphosphate could be performed during freeze-drying. We have demonstrated that the freeze-drying pressure modulates the degree of porosity. High freeze-drying pressure scaffolds presented pores with a mean diameter of 55 +/- 4 microm and a porosity of 33 +/- 12%, whereas low freeze-drying pressure scaffolds contained larger pores with a mean diameter of 243 +/- 14 microm and a porosity of 68 +/- 3%. Porous scaffolds of the desired shape could be easily obtained and were stable in culture medium for weeks. In vitro viable mesenchymal stem cells were found associated with porous scaffolds in higher proportions than with non-porous scaffolds. Moreover, cells penetrated deeper into scaffolds with larger pores. This novel combined freeze-drying/cross-linking processing of polysaccharides enabled the fabrication of biocompatible scaffolds with controlled porosity and architectures suitable for 3-D in vitro culture and biomedical applications.

Mesenchymal Stem Cell Allograft in Revision Foot and Ankle Surgery: A Clinical and Radiographic Analysis

A review was conducted of 23 patients who underwent implantation of mesenchymal stem cell allograft for revision foot or ankle surgery. Composed of viable mesenchymal stem cells derived from cadaveric donor tissue, the graft had osteogenic, osteoinductive, and osteoconductive properties, and was capable of direct new bone formation at the site of implantation. In all of the cases, radiographic new bone formation was observed at the area of implantation and a 91.3% union rate was observed, and no evidence of graft rejection or complications associated with implantation were recorded. Wilcoxon rank sum tests were used to determine whether gender, diabetes, chronic renal insufficiency, neuropathy, number of previous surgeries, and smoking were associated with time to healing. Spearman's rank correlation coefficient was calculated in an effort to identify the influence of continuous numeric variables on the time to bone healing. Based on the outcomes observed in this retrospective study, it appears that mesenchymal stem cell allograft is a beneficial biological adjunct to bone healing, and serves as a suitable bone autograft substitute in revision foot and ankle surgery. 4.

Ultrastructural analysis of adult stem cells embedded into a hyaluronan-based scaffold suitable for cardiac repair

The transplantation of scaffolds engineered with stem cells represents an encouraging tool for cardiac regeneration. In this study, mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs) were grown into a hyaluronan-benzyl ester biocompatible non-woven mesh (Hyaff-11®, Fidia Advanced Biopolymers, Abano Terme, Padua, Italy) to evaluate their morphology, proliferation and spatial organization. Rat bone marrow MSCs were seeded on the top layer of the scaffold at density of 2×106 cells/cm2. After 24 h most MSCs were attached to the fibres and had migrated into the scaffold. The number of viable MSCs increased over a 3-week period at a doubling rate of 1 day. Both fluorescence and optical microscopy showed that MSCs strongly adhered to each fibre as evidenced by their spread morphology. Cell-to-fibre focal adhesion points and extracellular matrix components were also seen by electron microscopy. Peripheral blood-derived human EPCs adhered to hyaluronan with less strength than MSCs, as shown by their round shape. EPCs slowly proliferated into the scaffold and exhibited structural and functional features similar to those of mature endothelial cells (i.e. channels for transcytosis, basement membrane production, ac-LDL uptake). Thus, we suggest that non-woven Hyaff-11® could be considered a scaffold useful for cardiac engineering because it allows appropriate MSC organization and EPC differentiation. This research was funded by a grant of Compagnia di San Paolo, Turin, Italy.

Can the Therapeutic Advantages of Allogenic Umbilical Cord Blood???Derived Stem Cells and Autologous Bone Marrow???Derived Mesenchymal Stem Cells Be Combined and Synergized?

Can the Therapeutic Advantages of Allogenic Umbilical Cord Blood???Derived Stem Cells and Autologous Bone Marrow???Derived Mesenchymal Stem Cells Be Combined and Synergized?

4:39144. Worst Case Scenario for Cell-Mediated BMP-2 Gene Therapy in Posterolateral Fusion

BACKGROUND CONTEXT: There are at most five studies mentioning safety after 10 or more years of investigation on cell-mediated bone-morphogenetic-protein gene therapy for orthopedic applications. Cells transfected with the cDNA for BMP when transplanted in vivo go on to produce BMP. Various BMPs induce bone formation, given a tissue environment containing viable mesenchymal stem cells. Various combinations of different cell types and viral vectors have been studied to achieve an optimal production of BMPs, and various techniques have been considered regarding feasibility in terms of harvesting and culturing the specific cell types. One of the criticisms of cell-mediated gene therapy is that once the modified cell is placed in vivo, the production of the desired molecule cannot be controlled. Safety must be critically evaluated before considering either ex vivo or in vivo gene therapy techniques for elective spinal surgery.

Po-Thur Eve General-22: 111In-Tropolone-Labeled Mesenchymal Stem Cells: In Vivo Radiotracer Kinetics

Direct in vitro labeling of cells with 111 In ‐tropolone followed by in vivoSPECTimaging gives no information about the fate of the cells but simply tells where the 111 In has gone. It is necessary to study the kinetics of 111 In label after transplantation and determine the connection between 111 In and the presence of viable cells. Two sets (n=5) of mesenchymal stem cells (MSC) were labeled with 111 In ‐tropolone and then killed by using an ultrasound probe to rupture the cell membrane or by freezing the cells at −80°C for 60min. The resulting cell debris and supernatant were used to label two new sets of MSC. The labeling efficiency was measured and compared to a control labeled with 111 In ‐tropolone. 1.5×107 MSC labeled with 1.32MBq 111 In were killed using the ultrasound probe and then injected into the myocardium of a canine (without infarction). Whole body and SPECTimages were acquired over 13 hrs post‐injection. The animal was then sacrificed and the amount of 111 In remaining in tissue samples from the heart was measured. (0.2±0.5)% and (0.3±0.5)% labeling efficiencies were found for cells labeled with ultrasound‐killed and frozen‐killed cells, while the labeling efficiency of the control cells was found to be (53.0±2.0)% for a 30min cell culture. After 13hrs, 111 In remained in the myocardium. Analysis of the 111 In SPECTimages indicated a biological half‐life of 2.3 hours. It was concluded that 111 In leaked from dead MSC does not label other viable MSC and will be rapidly cleared from the myocardium.

The effects of mesenchymal stem cells transduced with Akt in a porcine myocardial infarction model

This study was designed to examine whether mesenchymal stem cells (MSCs) transduced with Akt enhance cardiac repair after transplantation into the ischemic porcine heart. MSCs isolated from porcine bone marrow and transduced with myr-Akt were transplanted into porcine hearts after experimental myocardial infarction (MI) using intracoronary injection [Group I, vehicle; Group II, MSCs; Group III, Akt-MSCs]. Myocardial single photon emission tomography (M-SPECT) was performed to assess myocardial function and the infarcted area. Pigs were also sacrificed for immunohistochemical characterization and histologic analysis. In addition, in vitro assays were performed to examine the resistance of Akt-MSCs to H(2)O(2) stimulation. Transplantation of MSCs into the ischemic porcine myocardium (Group II) increased the left ventricular ejection fraction (DeltaLV EF; -6.3 +/- 15.1% versus 0.5 +/- 6.4%, P < 0.001) and decreased the Deltaarea of MI (6.8+/-5.6% versus -5.0+/-5.3%, P < 0.001) compared with the vehicle control (Group I). Transplantation of MSCs transduced with myr-Akt (Group III) resulted in further improvement in DeltaLV EF (-6.3 +/- 15.1% versus 5.8 +/- 11.3%, P < 0.001) and in Deltaarea of MI (6.8 +/- 5.6% versus -17.0 +/- 7.6%, P < 0.001). Akt-MSCs were more resistant to apoptosis, and the levels of extracellular signal-regulated protein kinase (ERK) activation and vascular endothelial growth factor (VEGF) were higher in H(2)O(2)-stimulated Akt-MSCs. Cellular transplantation of Akt-MSCs further enhances the repair of injured myocardium compared to MSC transplantation alone by increasing the number of viable MSCs after cellular transplantation.