In 2001, researchers at the University of California, Los Angeles, described the isolation of a new population of adult stem cells from liposuctioned adipose tissue that they initially termed Processed Lipoaspirate Cells or PLA cells. Since then, these stem cells have been renamed as Adipose-derived Stem Cells or ASCs and have gone on to become one of the most popular adult stem cells populations in the fields of stem cell research and regenerative medicine. Thousands of articles now describe the use of ASCs in a variety of regenerative animal models, including bone regeneration, peripheral nerve repair and cardiovascular engineering. Recent articles have begun to describe the myriad of uses for ASCs in the clinic. The protocol shown in this article outlines the basic procedure for manually and enzymatically isolating ASCs from large amounts of lipoaspirates obtained from cosmetic procedures. This protocol can easily be scaled up or down to accommodate the volume of lipoaspirate and can be adapted to isolate ASCs from fat tissue obtained through abdominoplasties and other similar procedures.
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Detection of MicroRNAs in Microglia by Real-time PCR in Normal CNS and During Neuroinflammation
Institutions: Harvard Medical School.
Microglia are cells of the myeloid lineage that reside in the central nervous system (CNS)1
. These cells play an important role in pathologies of many diseases associated with neuroinflammation such as multiple sclerosis (MS)2
. Microglia in a normal CNS express macrophage marker CD11b and exhibit a resting phenotype by expressing low levels of activation markers such as CD45. During pathological events in the CNS, microglia become activated as determined by upregulation of CD45 and other markers3
. The factors that affect microglia phenotype and functions in the CNS are not well studied. MicroRNAs (miRNAs) are a growing family of conserved molecules (~22 nucleotides long) that are involved in many normal physiological processes such as cell growth and differentiation4
and pathologies such as inflammation5
. MiRNAs downregulate the expression of certain target genes by binding complementary sequences of their mRNAs and play an important role in the activation of innate immune cells including macrophages6
. In order to investigate miRNA-mediated pathways that define the microglial phenotype, biological function, and to distinguish microglia from other types of macrophages, it is important to quantitatively assess the expression of particular microRNAs in distinct subsets of CNS-resident microglia. Common methods for measuring the expression of miRNAs in the CNS include quantitative PCR from whole neuronal tissue and in situ
hybridization. However, quantitative PCR from whole tissue homogenate does not allow the assessment of the expression of miRNA in microglia, which represent only 5-15% of the cells of neuronal tissue. Hybridization in situ
allows the assessment of the expression of microRNA in specific cell types in the tissue sections, but this method is not entirely quantitative. In this report we describe a quantitative and sensitive method for the detection of miRNA by real-time PCR in microglia isolated from normal CNS or during neuroinflammation using experimental autoimmune encephalomyelitis (EAE), a mouse model for MS. The described method will be useful to measure the level of expression of microRNAs in microglia in normal CNS or during neuroinflammation associated with various pathologies including MS, stroke, traumatic injury, Alzheimer's disease and brain tumors.
Immunology, Issue 65, Neuroscience, Genetics, microglia, macrophages, microRNA, brain, mouse, real-time PCR, neuroinflammation
Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library
The Target ID Library is designed to assist in discovery and identification of microRNA (miRNA) targets. The Target ID Library is a plasmid-based, genome-wide cDNA library cloned into the 3'UTR downstream from the dual-selection fusion protein, thymidine kinase-zeocin (TKzeo). The first round of selection is for stable transformants, followed with introduction of a miRNA of interest, and finally, selecting for cDNAs containing the miRNA's target. Selected cDNAs are identified by sequencing (see Figure 1-3 for Target ID Library Workflow and details).
To ensure broad coverage of the human transcriptome, Target ID Library cDNAs were generated via oligo-dT priming using a pool of total RNA prepared from multiple human tissues and cell lines. Resulting cDNA range from 0.5 to 4 kb, with an average size of 1.2 kb, and were cloned into the p3΄TKzeo dual-selection plasmid (see Figure 4 for plasmid map). The gene targets represented in the library can be found on the Sigma-Aldrich webpage. Results from Illumina sequencing (Table 3
), show that the library includes 16,922 of the 21,518 unique genes in UCSC RefGene (79%), or 14,000 genes with 10 or more reads (66%).
Genetics, Issue 62, Target ID, miRNA, ncRNA, RNAi, genomics
Repair of a Critical-sized Calvarial Defect Model Using Adipose-derived Stromal Cells Harvested from Lipoaspirate
Institutions: Stanford University , Duke University , Saint Joseph Mercy Hospital, University of California, San Francisco , University of California, Los Angeles .
Craniofacial skeletal repair and regeneration offers the promise of de novo
tissue formation through a cell-based approach utilizing stem cells. Adipose-derived stromal cells (ASCs) have proven to be an abundant source of multipotent stem cells capable of undergoing osteogenic, chondrogenic, adipogenic, and myogenic differentiation. Many studies have explored the osteogenic potential of these cells in vivo
with the use of various scaffolding biomaterials for cellular delivery. It has been demonstrated that by utilizing an osteoconductive, hydroxyapatite-coated poly(lactic-co-glycolic acid) (HA-PLGA) scaffold seeded with ASCs, a critical-sized calvarial defect, a defect that is defined by its inability to undergo spontaneous healing over the lifetime of the animal, can be effectively show robust osseous regeneration. This in vivo
model demonstrates the basis of translational approaches aimed to regenerate the bone tissue - the cellular component and biological matrix. This method serves as a model for the ultimate clinical application of a progenitor cell towards the repair of a specific tissue defect.
Medicine, Issue 68, Stem Cells, Skeletal Tissue Engineering, Calvarial Defect, Scaffold, Tissue Regeneration, adipose-derived stromal cells
Constructing a Collagen Hydrogel for the Delivery of Stem Cell-loaded Chitosan Microspheres
Institutions: United States Army Institute of Surgical Research.
Multipotent stem cells have been shown to be extremely useful in the field of regenerative medicine1-3
. However, in order to use these cells effectively for tissue regeneration, a number of variables must be taken into account. These variables include: the total volume and surface area of the implantation site, the mechanical properties of the tissue and the tissue microenvironment, which includes the amount of vascularization and the components of the extracellular matrix. Therefore, the materials being used to deliver these cells must be biocompatible with a defined chemical composition while maintaining a mechanical strength that mimics the host tissue. These materials must also be permeable to oxygen and nutrients to provide a favorable microenvironment for cells to attach and proliferate. Chitosan, a cationic polysaccharide with excellent biocompatibility, can be easily chemically modified and has a high affinity to bind with in vivo
. Chitosan mimics the glycosaminoglycan portion of the extracellular matrix, enabling it to function as a substrate for cell adhesion, migration and proliferation. In this study we utilize chitosan in the form of microspheres to deliver adipose-derived stem cells (ASC) into a collagen based three-dimensional scaffold6
. An ideal cell-to-microsphere ratio was determined with respect to incubation time and cell density to achieve maximum number of cells that could be loaded. Once ASC are seeded onto the chitosan microspheres (CSM), they are embedded in a collagen scaffold and can be maintained in culture for extended periods. In summary, this study provides a method to precisely deliver stem cells within a three dimensional biomaterial scaffold.
Bioengineering, Issue 64, Biomedical Engineering, Tissue Engineering, chitosan, microspheres, collagen, hydrogel, cell delivery, adipose-derived stem cells, ASC, CSM
Retroviral Infection of Murine Embryonic Stem Cell Derived Embryoid Body Cells for Analysis of Hematopoietic Differentiation
Institutions: Harper Cancer Research Institute, Indiana University School of Medicine, University of Notre Dame.
Embryonic stem cells (ESCs) are an outstanding model for elucidating the molecular mechanisms of cellular differentiation. They are especially useful for investigating the development of early hematopoietic progenitor cells (HPCs). Gene expression in ESCs can be manipulated by several techniques that allow the role for individual molecules in development to be determined. One difficulty is that expression of specific genes often has different phenotypic effects dependent on their temporal expression. This problem can be circumvented by the generation of ESCs that inducibly express a gene of interest using technology such as the doxycycline-inducible transgene system. However, generation of these inducible cell lines is costly and time consuming. Described here is a method for disaggregating ESC-derived embryoid bodies (EBs) into single cell suspensions, retrovirally infecting the cell suspensions, and then reforming the EBs by hanging drop. Downstream differentiation is then evaluated by flow cytometry. Using this protocol, it was demonstrated that exogenous expression of a microRNA gene at the beginning of ESC differentiation blocks HPC generation. However, when expressed in EB derived cells after nascent mesoderm is produced, the microRNA gene enhances hematopoietic differentiation. This method is useful for investigating the role of genes after specific germ layer tissue is derived.
Cellular Biology, Issue 92, Embryonic stem cell, Embryoid body, Hematopoietic Progenitor Cells, Retrovirus, Gene Expression, Temporal Gene Expression
Human Cartilage Tissue Fabrication Using Three-dimensional Inkjet Printing Technology
Institutions: Rensselaer Polytechnic Institute, Stemorgan Inc., Technical University of Munich, Wuhan University, The Scripps Research Institute, Tokyo University of Science.
Bioprinting, which is based on thermal inkjet printing, is one of the most attractive enabling technologies in the field of tissue engineering and regenerative medicine. With digital control cells, scaffolds, and growth factors can be precisely deposited to the desired two-dimensional (2D) and three-dimensional (3D) locations rapidly. Therefore, this technology is an ideal approach to fabricate tissues mimicking their native anatomic structures. In order to engineer cartilage with native zonal organization, extracellular matrix composition (ECM), and mechanical properties, we developed a bioprinting platform using a commercial inkjet printer with simultaneous photopolymerization capable for 3D cartilage tissue engineering. Human chondrocytes suspended in poly(ethylene glycol) diacrylate (PEGDA) were printed for 3D neocartilage construction via layer-by-layer assembly. The printed cells were fixed at their original deposited positions, supported by the surrounding scaffold in simultaneous photopolymerization. The mechanical properties of the printed tissue were similar to the native cartilage. Compared to conventional tissue fabrication, which requires longer UV exposure, the viability of the printed cells with simultaneous photopolymerization was significantly higher. Printed neocartilage demonstrated excellent glycosaminoglycan (GAG) and collagen type II production, which was consistent with gene expression. Therefore, this platform is ideal for accurate cell distribution and arrangement for anatomic tissue engineering.
Bioengineering, Issue 88, cartilage, inkjet printing, chondrocytes, hydrogel, photopolymerization, tissue engineering
Establishment of a Surgically-induced Model in Mice to Investigate the Protective Role of Progranulin in Osteoarthritis
Institutions: NYU Hospital for Joint Diseases, New York University Medical Center.
Destabilization of medial meniscus (DMM) model is an important tool for studying the pathophysiological roles of numerous arthritis associated molecules in the pathogenesis of osteoarthritis (OA) in vivo
. However, the detailed, especially the visualized protocol for establishing this complicated model in mice, is not available. Herein we took advantage of wildtype and progranulin (PGRN)-/- mice as examples to introduce a protocol for inducing DMM model in mice, and compared the onset of OA following establishment of this surgically induced model. The operations performed on mice were either sham operation, which just opened joint capsule, or DMM operation, which cut the menisco-tibial ligament and caused destabilization of medial meniscus. Osteoarthritis severity was evaluated using histological assay (e.g.
Safranin O staining), expressions of OA-associated genes, degradation of cartilage extracellular matrix molecules, and osteophyte formation. DMM operation successfully induced OA initiation and progression in both wildtype and PGRN-/- mice, and loss of PGNR growth factor led to a more severe OA phenotype in this surgically induced model.
Bioengineering, Issue 84, Mouse, Cartilage, Surgery, Osteoarthritis, degenerative arthritis, progranulin, destabilization of medial meniscus (DMM)
Profiling of Estrogen-regulated MicroRNAs in Breast Cancer Cells
Institutions: University of Houston.
Estrogen plays vital roles in mammary gland development and breast cancer progression. It mediates its function by binding to and activating the estrogen receptors (ERs), ERα, and ERβ. ERα is frequently upregulated in breast cancer and drives the proliferation of breast cancer cells. The ERs function as transcription factors and regulate gene expression. Whereas ERα's regulation of protein-coding genes is well established, its regulation of noncoding microRNA (miRNA) is less explored. miRNAs play a major role in the post-transcriptional regulation of genes, inhibiting their translation or degrading their mRNA. miRNAs can function as oncogenes or tumor suppressors and are also promising biomarkers. Among the miRNA assays available, microarray and quantitative real-time polymerase chain reaction (qPCR) have been extensively used to detect and quantify miRNA levels. To identify miRNAs regulated by estrogen signaling in breast cancer, their expression in ERα-positive breast cancer cell lines were compared before and after estrogen-activation using both the µParaflo-microfluidic microarrays and Dual Labeled Probes-low density arrays. Results were validated using specific qPCR assays, applying both Cyanine dye-based and Dual Labeled Probes-based chemistry. Furthermore, a time-point assay was used to identify regulations over time. Advantages of the miRNA assay approach used in this study is that it enables a fast screening of mature miRNA regulations in numerous samples, even with limited sample amounts. The layout, including the specific conditions for cell culture and estrogen treatment, biological and technical replicates, and large-scale screening followed by in-depth confirmations using separate techniques, ensures a robust detection of miRNA regulations, and eliminates false positives and other artifacts. However, mutated or unknown miRNAs, or regulations at the primary and precursor transcript level, will not be detected. The method presented here represents a thorough investigation of estrogen-mediated miRNA regulation.
Medicine, Issue 84, breast cancer, microRNA, estrogen, estrogen receptor, microarray, qPCR
Adenoviral Transduction of Naive CD4 T Cells to Study Treg Differentiation
Institutions: Helmholtz Zentrum München.
Regulatory T cells (Tregs) are essential to provide immune tolerance to self as well as to certain foreign antigens. Tregs can be generated from naive CD4 T cells in vitro
with TCR- and co-stimulation in the presence of TGFβ and IL-2. This bears enormous potential for future therapies, however, the molecules and signaling pathways that control differentiation are largely unknown.
Primary T cells can be manipulated through ectopic gene expression, but common methods fail to target the most important naive state of the T cell prior to primary antigen recognition. Here, we provide a protocol to express ectopic genes in naive CD4 T cells in vitro
before inducing Treg differentiation. It applies transduction with the replication-deficient adenovirus and explains its generation and production. The adenovirus can take up large inserts (up to 7 kb) and can be equipped with promoters to achieve high and transient overexpression in T cells. It effectively transduces naive mouse T cells if they express a transgenic Coxsackie adenovirus receptor (CAR). Importantly, after infection the T cells remain naive (CD44low
) and resting (CD25-
) and can be activated and differentiated into Tregs similar to non-infected cells. Thus, this method enables manipulation of CD4 T cell differentiation from its very beginning. It ensures that ectopic gene expression is already in place when early signaling events of the initial TCR stimulation induces cellular changes that eventually lead into Treg differentiation.
Immunology, Issue 78, Cellular Biology, Molecular Biology, Medicine, Biomedical Engineering, Bioengineering, Infection, Genetics, Microbiology, Virology, T-Lymphocytes, Regulatory, CD4-Positive T-Lymphocytes, Regulatory, Adenoviruses, Human, MicroRNAs, Antigens, Differentiation, T-Lymphocyte, Gene Transfer Techniques, Transduction, Genetic, Transfection, Adenovirus, gene transfer, microRNA, overexpression, knock down, CD4 T cells, in vitro differentiation, regulatory T cell, virus, cell, flow cytometry
Preparation of Primary Myogenic Precursor Cell/Myoblast Cultures from Basal Vertebrate Lineages
Institutions: University of Alabama at Birmingham, INRA UR1067, INRA UR1037.
Due to the inherent difficulty and time involved with studying the myogenic program in vivo
, primary culture systems derived from the resident adult stem cells of skeletal muscle, the myogenic precursor cells (MPCs), have proven indispensible to our understanding of mammalian skeletal muscle development and growth. Particularly among the basal taxa of Vertebrata,
however, data are limited describing the molecular mechanisms controlling the self-renewal, proliferation, and differentiation of MPCs. Of particular interest are potential mechanisms that underlie the ability of basal vertebrates to undergo considerable postlarval skeletal myofiber hyperplasia (i.e.
teleost fish) and full regeneration following appendage loss (i.e.
urodele amphibians). Additionally, the use of cultured myoblasts could aid in the understanding of regeneration and the recapitulation of the myogenic program and the differences between them. To this end, we describe in detail a robust and efficient protocol (and variations therein) for isolating and maintaining MPCs and their progeny, myoblasts and immature myotubes, in cell culture as a platform for understanding the evolution of the myogenic program, beginning with the more basal vertebrates. Capitalizing on the model organism status of the zebrafish (Danio rerio
), we report on the application of this protocol to small fishes of the cyprinid clade Danioninae
. In tandem, this protocol can be utilized to realize a broader comparative approach by isolating MPCs from the Mexican axolotl (Ambystomamexicanum
) and even laboratory rodents. This protocol is now widely used in studying myogenesis in several fish species, including rainbow trout, salmon, and sea bream1-4
Basic Protocol, Issue 86, myogenesis, zebrafish, myoblast, cell culture, giant danio, moustached danio, myotubes, proliferation, differentiation, Danioninae, axolotl
Engineering a Bilayered Hydrogel to Control ASC Differentiation
Institutions: United States Army Institute of Surgical Research, The University of Texas at Austin.
Natural polymers over the years have gained more importance because of their host biocompatibility and ability to interact with cells in vitro
and in vivo.
An area of research that holds promise in regenerative medicine is the combinatorial use of novel biomaterials and stem cells. A fundamental strategy in the field of tissue engineering is the use of three-dimensional scaffold (e.g., decellularized extracellular matrix, hydrogels, micro/nano particles) for directing cell function. This technology has evolved from the discovery that cells need a substrate upon which they can adhere, proliferate, and express their differentiated cellular phenotype and function 2-3
. More recently, it has also been determined that cells not only use these substrates for adherence, but also interact and take cues from the matrix substrate (e.g., extracellular matrix, ECM)4
. Therefore, the cells and scaffolds have a reciprocal connection that serves to control tissue development, organization, and ultimate function. Adipose-derived stem cells (ASCs) are mesenchymal, non-hematopoetic stem cells present in adipose tissue that can exhibit multi-lineage differentiation and serve as a readily available source of cells (i.e. pre-vascular endothelia and pericytes). Our hypothesis is that adipose-derived stem cells can be directed toward differing phenotypes simultaneously by simply co-culturing them in bilayered matrices1
. Our laboratory is focused on dermal wound healing. To this end, we created a single composite matrix from the natural biomaterials, fibrin, collagen, and chitosan that can mimic the characteristics and functions of a dermal-specific wound healing ECM environment.
Bioengineering, Issue 63, Biomedical Engineering, Tissue Engineering, chitosan, microspheres, collagen, hydrogel, PEG fibrin, cell delivery, adipose-derived stem cells, ASC, CSM
Isolation of Blood-vessel-derived Multipotent Precursors from Human Skeletal Muscle
Institutions: University of Pittsburgh, University of Pittsburgh, Nazarbayev University, University of California at Los Angeles, Erasmus MC Stem Cell Institute, Oregon Health & Science University, Queen's Medical Research Institute and University of Edinburgh, University of California at Los Angeles, University of Pittsburgh.
Since the discovery of mesenchymal stem/stromal cells (MSCs), the native identity and localization of MSCs
have been obscured by their retrospective isolation in culture. Recently, using fluorescence-activated cell sorting (FACS), we and other researchers prospectively identified and purified three subpopulations of multipotent precursor cells associated with the vasculature of human skeletal muscle. These three cell populations: myogenic endothelial cells (MECs), pericytes (PCs), and adventitial cells (ACs), are localized respectively to the three structural layers of blood vessels: intima, media, and adventitia. All of these human blood-vessel-derived stem cell (hBVSC) populations not only express classic MSC markers but also possess mesodermal developmental potentials similar to typical MSCs. Previously, MECs, PCs, and ACs have been isolated through distinct protocols and subsequently characterized in separate studies. The current isolation protocol, through modifications to the isolation process and adjustments in the selective cell surface markers, allows us to simultaneously purify all three hBVSC subpopulations by FACS from a single human muscle biopsy. This new method will not only streamline the isolation of multiple BVSC subpopulations but also facilitate future clinical applications of hBVSCs for distinct therapeutic purposes.
Cellular Biology, Issue 90, Blood Vessel; Pericyte; Adventitial Cell; Myogenic Endothelial Cell; Multipotent Precursor
A 3D System for Culturing Human Articular Chondrocytes in Synovial Fluid
Institutions: Tufts University School of Medicine, Tufts Medical Center.
Cartilage destruction is a central pathological feature of osteoarthritis, a leading cause of disability in the US. Cartilage in the adult does not regenerate very efficiently in vivo
; and as a result, osteoarthritis leads to irreversible cartilage loss and is accompanied by chronic pain and immobility 1,2
. Cartilage tissue engineering offers promising potential to regenerate and restore tissue function. This technology typically involves seeding chondrocytes into natural or synthetic scaffolds and culturing the resulting 3D construct in a balanced medium over a period of time with a goal of engineering a biochemically and biomechanically mature tissue that can be transplanted into a defect site in vivo 3-6
. Achieving an optimal condition for chondrocyte growth and matrix deposition is essential for the success of cartilage tissue engineering.
In the native joint cavity, cartilage at the articular surface of the bone is bathed in synovial fluid. This clear and viscous fluid provides nutrients to the avascular articular cartilage and contains growth factors, cytokines and enzymes that are important for chondrocyte metabolism 7,8
. Furthermore, synovial fluid facilitates low-friction movement between cartilaginous surfaces mainly through secreting two key components, hyaluronan and lubricin 9 10
. In contrast, tissue engineered cartilage is most often cultured in artificial media. While these media are likely able to provide more defined conditions for studying chondrocyte metabolism, synovial fluid most accurately reflects the natural environment of which articular chondrocytes reside in.
Indeed, synovial fluid has the advantage of being easy to obtain and store, and can often be regularly replenished by the body. Several groups have supplemented the culture medium with synovial fluid in growing human, bovine, rabbit and dog chondrocytes, but mostly used only low levels of synovial fluid (below 20%) 11-25
. While chicken, horse and human chondrocytes have been cultured in the medium with higher percentage of synovial fluid, these culture systems were two-dimensional 26-28
. Here we present our method of culturing human articular chondrocytes in a 3D system with a high percentage of synovial fluid (up to 100%) over a period of 21 days. In doing so, we overcame a major hurdle presented by the high viscosity of the synovial fluid. This system provides the possibility of studying human chondrocytes in synovial fluid in a 3D setting, which can be further combined with two other important factors (oxygen tension and mechanical loading) 29,30
that constitute the natural environment for cartilage to mimic the natural milieu for cartilage growth. Furthermore, This system may also be used for assaying synovial fluid activity on chondrocytes and provide a platform for developing cartilage regeneration technologies and therapeutic options for arthritis.
Cellular Biology, Issue 59, Chondrocytes, articular, human, synovial fluid, alginate bead, 3D culture
High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry
Institutions: Medical College of Wisconsin, Stanford University School of Medicine, Medical College of Wisconsin, Hong Kong University, Johns Hopkins University School of Medicine, Medical College of Wisconsin.
There is an urgent need to develop approaches for repairing the damaged heart, discovering new therapeutic drugs that do not have toxic effects on the heart, and improving strategies to accurately model heart disease. The potential of exploiting human induced pluripotent stem cell (hiPSC) technology to generate cardiac muscle “in a dish” for these applications continues to generate high enthusiasm. In recent years, the ability to efficiently generate cardiomyogenic cells from human pluripotent stem cells (hPSCs) has greatly improved, offering us new opportunities to model very early stages of human cardiac development not otherwise accessible. In contrast to many previous methods, the cardiomyocyte differentiation protocol described here does not require cell aggregation or the addition of Activin A or BMP4 and robustly generates cultures of cells that are highly positive for cardiac troponin I and T (TNNI3, TNNT2), iroquois-class homeodomain protein IRX-4 (IRX4), myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC2v) and myosin regulatory light chain 2, atrial isoform (MLC2a) by day 10 across all human embryonic stem cell (hESC) and hiPSC lines tested to date. Cells can be passaged and maintained for more than 90 days in culture. The strategy is technically simple to implement and cost-effective. Characterization of cardiomyocytes derived from pluripotent cells often includes the analysis of reference markers, both at the mRNA and protein level. For protein analysis, flow cytometry is a powerful analytical tool for assessing quality of cells in culture and determining subpopulation homogeneity. However, technical variation in sample preparation can significantly affect quality of flow cytometry data. Thus, standardization of staining protocols should facilitate comparisons among various differentiation strategies. Accordingly, optimized staining protocols for the analysis of IRX4, MLC2v, MLC2a, TNNI3, and TNNT2 by flow cytometry are described.
Cellular Biology, Issue 91, human induced pluripotent stem cell, flow cytometry, directed differentiation, cardiomyocyte, IRX4, TNNI3, TNNT2, MCL2v, MLC2a
Implantation of Ferumoxides Labeled Human Mesenchymal Stem Cells in Cartilage Defects
Institutions: Medical Center, University of California San Francisco.
The field of tissue engineering integrates the principles of engineering, cell biology and medicine towards the regeneration of specific cells and functional tissue. Matrix associated stem cell implants (MASI) aim to regenerate cartilage defects due to arthritic or traumatic joint injuries. Adult mesenchymal stem cells (MSCs) have the ability to differentiate into cells of the chondrogenic lineage and have shown promising results for cell-based articular cartilage repair technologies. Autologous MSCs can be isolated from a variety of tissues, can be expanded in cell cultures without losing their differentiation potential, and have demonstrated chondrogenic differentiation in vitro
and in vivo1, 2
In order to provide local retention and viability of transplanted MSCs in cartilage defects, a scaffold is needed, which also supports subsequent differentiation and proliferation. The architecture of the scaffold guides tissue formation and permits the extracellular matrix, produced by the stem cells, to expand. Previous investigations have shown that a 2% agarose scaffold may support the development of stable hyaline cartilage and does not induce immune responses3
Long term retention of transplanted stem cells in MASI is critical for cartilage regeneration. Labeling of MSCs with iron oxide nanoparticles allows for long-term in vivo
tracking with non-invasive MR imaging techniques4
This presentation will demonstrate techniques for labeling MSCs with iron oxide nanoparticles, the generation of cell-agarose constructs and implantation of these constructs into cartilage defects. The labeled constructs can be tracked non-invasively with MR-Imaging.
Cellular Biology, Issue 38, Stem cells, cartilage defect, agarose, scaffold, tissue engineering, implantation, MASI
Electrochemotherapy of Tumours
Institutions: Institute of Oncology Ljubljana, University of Ljubljana.
Electrochemotherapy is a combined use of certain chemotherapeutic drugs and electric pulses applied to the treated tumour nodule. Local application of electric pulses to the tumour increases drug delivery into cells, specifically at the site of electric pulse application. Drug uptake by delivery of electric pulses is increased for only those chemotherapeutic drugs whose transport through the plasma membrane is impeded. Among many drugs that have been tested so far, bleomycin and cisplatin found their way from preclinical testing to clinical use. Clinical data collected within a number of clinical studies indicate that approximately 80% of the treated cutaneous and subcutaneous tumour nodules of different malignancies are in an objective response, from these, approximately 70% in complete response after a single application of electrochemotherapy. Usually only one treatment is needed, however, electrochemotherapy can be repeated several times every few weeks with equal effectiveness each time. The treatment results in an effective eradication of the treated nodules, with a good cosmetic effect without tissue scarring.
Medicine, Issue 22, electrochemotherapy, electroporation, cisplatin, bleomycin, malignant tumours, cutaneous lesions
Reverse Total Shoulder Arthroplasty
Institutions: Case Western Reserve University.
Reverse total shoulder arthroplasty was initially approved for use in rotator cuff arthropathy and well as chronic pseudoparalysis without arthritis in patients who were not appropriate for tendon transfer reconstructions. Traditional surgical options for these patients were limited and functional results were sub-optimal and at times catastrophic. The use of reverse shoulder arthroplasty has been found to effectively restore these patients function and relieve symptoms associated with their disease. The procedure can be done through two approaches, the deltopectoral or the superolateral. Complication rates associated with the use of the prosthesis have ranged from 8-60% with more recent reports trending lower as experienced is gained. Salvage options for a failed reverse shoulder prosthesis are limited and often have significant associated disability. Indications for the use of this prosthesis continue to be evaluated including its use for revision arthroplasty, proximal humeral fracture and tumor. Careful patient selection is essential because of the significant risks associated with the procedure.
Medicine, Issue 53, Reverse, Total, Shoulder, Arthroplasty, Rotator Cuff, Arthropathy, Arthritis, Glenoid, Humerus, Fracture