Birgit Weyand

Isolation, Characterization, Differentiation, and Application of Adipose-Derived Stem Cells

While bone marrow-derived mesenchymal stem cells are known and have been investigated for a long time, mesenchymal stem cells derived from the adipose tissue were identified as such by Zuk et al. in 2001. However, as subcutaneous fat tissue is a rich source which is much more easily accessible than bone marrow and thus can be reached by less invasive procedures, adipose-derived stem cells have moved into the research spotlight over the last 8 years.Isolation of stromal cell fractions involves centrifugation, digestion, and filtration, resulting in an adherent cell population containing mesenchymal stem cells; these can be subdivided by cell sorting and cultured under common conditions.They seem to have comparable properties to bone marrow-derived mesenchymal stem cells in their differentiation abilities as well as a favorable angiogenic and anti-inflammatory cytokine secretion profile and therefore have become widely used in tissue engineering and clinical regenerative medicine.

Alignment-Annotator web server: rendering and annotating sequence alignments

Alignment-Annotator is a novel web service designed to generate interactive views of annotated nucleotide and amino acid sequence alignments (i) de novo and (ii) embedded in other software. All computations are performed at server side. Interactivity is implemented in HTML5, a language native to web browsers. The alignment is initially displayed using default settings and can be modified with the graphical user interfaces. For example, individual sequences can be reordered or deleted using drag and drop, amino acid color code schemes can be applied and annotations can be added. Annotations can be made manually or imported (BioDAS servers, the UniProt, the Catalytic Site Atlas and the PDB). Some edits take immediate effect while others require server interaction and may take a few seconds to execute. The final alignment document can be downloaded as a zip-archive containing the HTML files. Because of the use of HTML the resulting interactive alignment can be viewed on any platform including Windows, Mac OS X, Linux, Android and iOS in any standard web browser. Importantly, no plugins nor Java are required and therefore Alignment-Anotator represents the first interactive browser-based alignment visualization. Availability: http://www.bioinformatics.org/strap/aa/ and http://strap.charite.de/aa/.

Stem Cell Differentiation Depending on Different Surfaces

Mesenchymal stem cells and 3D biomaterials are a potent assembly in tissue engineering. Today, a sizable number of biomaterials has been characterized for special tissue engineering applications. However, diverse material properties, such as soft or hard biomaterials, have a specific influence on cell behavior. Not only the cell attachment and proliferation, but also differentiation is controlled by the microenvironment. Material characteristics such as pore size, stiffness, roughness, and geometry affect not only the cell attachment and proliferation, but also the differentiation behavior of mesenchymal stem cells. Optimization of these features might enable direct differentiation without adjustment of the culture medium by applying expensive growth or differentiation factors. Future aspects include the design of multilayered biomaterials, where each zone fulfills a distinct function. Moreover, the embedding of growth and differentiation factors into the matrix with a controlled release rate might be advantageous to direct differentiation.

Rehabilitation of burn patients: An underestimated socio-economic burden

PURPOSE Patients with burns utilise intensive medical care and rehabilitation. Deep dermal burns lead to scar contractures. Virtually no published data exists on costs for treatment of acute burns in comparison to burn sequelae. Our purpose was to collect financial data on burn therapy to estimate the socio-economic burden of thermal injuries. METHODS German-DRG for in-patient treatment of burns was collected from our burn center. DRG-related T95.- coding served as a search tool for burn associated sequelae. To include rehabilitation costs, data from the largest health care insurance and a workmen compensation fund were acquired. FINDINGS Acute burn treatment comprised 92% of costs for intensive care with approximately 4.600 EUR per percent total burned surface area (TBSA). Expenses for non-intensive care patients were significantly lower than for burn sequelae. Rehabilitation expenses were 4.4-fold higher than costs for acute burns including 59% for manual therapy and 37% for auxiliary material. CONCLUSIONS TBSA multiplied by factor 4600 could serve for cost calculation of severely burned patients. Approximately 0.3 billion EUR in total or 270.000 EUR per patient/year were spent on burn sequelae. Early admission to specialized burn centers is advocated with state-of-the-art treatment to minimize burn sequelae and health care expenses.

Potential for Osteogenic and Chondrogenic Differentiation of MSC

The introduction of mesenchymal stem cells (MSC) into the field of tissue engineering for bone and cartilage repair is a promising development, since these cells can be expanded ex vivo to clinically relevant numbers and, after expansion, retain their ability to differentiate into different cell lineages. Mesenchymal stem cells isolated from various tissues have been intensively studied and characterized by many research groups. To obtain functionally active differentiated tissue, tissue engineered constructs are cultivated in vitro statically or dynamically in bioreactors under controlled conditions. These conditions include special cell culture media, addition of signalling molecules, various physical and chemical factors and the application of different mechanical stimuli. Oxygen concentration in the culture environment is also a significant factor which influences MSC proliferation, stemness and differentiation capacity. Knowledge of the different aspects which affect MSC differentiation in vivo and in vitro will help researchers to achieve directed cell fate without the addition of differentiation agents in concentrations above the physiological range.

Fluid Dynamics in Bioreactor Design: Considerations for the Theoretical and Practical Approach

The following chapter summarizes principles of fluid dynamics in bioreactor design with a focus on mammalian cell-culture systems.

A Differential Pressure Laminar Flow Reactor Supports Osteogenic Differentiation and Extracellular Matrix Formation from Adipose Mesenchymal Stem Cells in a Macroporous Ceramic Scaffold

Abstract We present a laminar flow reactor for bone tissue engineering that was developed based on a computational fluid dynamics model. The bioreactor design permits a laminar flow field through its specific internal shape. An integrated bypass system that prevents pressure build-up through bypass openings for pressure release allows for a constant pressure environment during the changing of permeability values that are caused by cellular growth within a porous scaffold. A macroporous ceramic scaffold, composed of zirconium dioxide, was used as a test biomaterial that studies adipose stem cell behavior within a controlled three-dimensional (3D) flow and pressure environment. The topographic structure of the material provided a basis for stem cell proliferation and differentiation toward the osteogenic lineage. Dynamic culture conditions in the bioreactor supported cell viability during long-term culture and induced cell cluster formation and extra-cellular matrix deposition within the porous scaffold, though no complete closure of the pores with new-formed tissue was observed. We postulate that our system is suitable for studying fluid shear stress effects on stem cell proliferation and differentiation toward bone formation in tissue-engineered 3D constructs.

Development of a Laminar Flow Bioreactor by Computational Fluid Dynamics

The purpose of this study is to improve the design of a bioreactor for growing bone and other three-dimensional tissues using a computational fluid dynamics (CFD) software to simulate flow through a porous scaffold, and to recommend design changes based on the results. Basic requirements for CFD modeling were that the flow in the reactor should be laminar and any flow stagnation should be avoided in order to support cellular growth within the scaffold. We simulated three different designs with different permeability values of the scaffold and tissue. Model simulation addressed flow patterns in combination with pressure distribution within the bioreactor. Pressure build-up and turbulent flow within the reactor was solved by introduction of an integrated bypass system for pressure release. The use of CFD afforded direct feedback to optimize the bioreactor design.

Mesenchymal Stem Cells - Basics and Clinical Application II

Engineered MSCs from Patient-Specific iPS Cells, by Irina Eberle, Mohsen Moslem, Reinhard Henschler, Tobias Cantz Fate of Intravenously Injected Mesenchymal Stem Cells and Significance for Clinical Application, by Beate Wagner, Reinhard Henschler The Implications of Stem Cell Applications for Diseases of the Respiratory System, by Mei Ling Lim, Philipp Jungebluth, Paolo Macchiarini Potential of Mesenchymal Stem Cell Applications in Plastic and Reconstructive Surgery, by Birgit Weyand, Peter M. Vogt General Principles for the Regeneration of Bone and Cartilage, by Michael Jagodzinski, C. Haasper Adult Mesenchymal Stem Cells Explored in the Dental Field, by K. M. Fawzy El-Sayed, C. Dorfer, F. Fandrich, F. Gieseler, M. H. Moustafa, H. Ungefroren Mesenchymal Stem Cell Therapy and Lung Diseases, by Khondoker M. Akram, Sohel Samad, Monica Spiteri, Nicholas R. Forsyth Mesenchymal Stem Cells as Cellular Immunotherapeutics in Allogeneic Hematopoietic Stem Cell Transplantation, by Claudia Papewalis, Daniela Topolar, Barbara Gotz, Stefan Schonberger, Dagmar Dilloo New Cell-Based Therapy Paradigm: Induction of Bone Marrow-Derived Multipotent Mesenchymal Stromal Cells into Pro-Inflammatory MSC1 and Anti-inflammatory MSC2 Phenotypes, by Aline M. Betancourt Interactions Between Mesenchymal Stem Cells and Dendritic Cells, by Grazia Maria Spaggiari, Lorenzo Moretta MSC and Tumors: Homing, Differentiation, and Secretion Influence Therapeutic Potential, by Naomi Dsouza, Jorge Sans Burns, Giulia Grisendi, Olivia Candini, Elena Veronesi, Serena Piccinno, Edwin M. Horwitz, Paolo Paolucci, Pierfranco Conte, Massimo Dominici Sources of Mesenchymal Stem Cells: Current and Future Clinical Use, by Michela Pozzobon, Martina Piccoli, Paolo De Coppi Role of the EU Framework in Regulation of Stem Cell-Based Products, by Giovanni Migliaccio, Cristina Pintus

Altered VEGF-A and receptor mRNA expression profiles, and identification of VEGF144 in foetal rat calvaria cells, in coculture with microvascular endothelial cells.

Cellular proliferation and differentiation during angiogenesis and osteogenesis require the communication of different cell types through growth factors and their receptors. Vascular endothelial growth factor (VEGF‐A) plays an important role in osteoblast and endothelial cell intercommunication. We have investigated the effect of monocultures and indirect coculture of foetal rat calvarial (FRC) osteoblasts and microvascular endothelial cells (ECs) on nodule formation, proliferation, and mRNA‐expression of VEGF‐A and its receptors during culturing. Despite increased nodule formation in the presence of dexamethasone (Dex) in monocultures, the number of nodules and alkaline phosphatise activity were decreased in cocultured FRCs. VEGF mRNA expression over the differentiation period showed the expression of most Vegf isoforms is biphasic in both FRCs and ECs, whereas receptor expression was quite variable; however, that of Np‐2 in FRCs increased steadily and significantly from 8 h to 14 days after an initial drop in expression. Significant changes in the proportion of Vegfa by Day 14 were noted mainly in the matrix‐bound variants Vegf144 and Vegf188 in ECs and osteoblasts, respectively. Less striking results were seen in the expression of the soluble isoforms in either cell type. These results have identified expression of Vegf144 in osteoblasts, suggesting a possible autocrine and/or paracrine role that is affecting osteoblast mineralisation along with Vegf188, as well as possible early roles of these isoforms in initial cell attachment. Further study of VEGF expression in coculture and Vegf144 will lead to better understanding of its role in cell–cell communication and bone development.