Bio-Medical Materials and Engineering - Volume 16, issue 4

Authors: Pulkkinen, Hertta | Tiitu, Virpi | Lammentausta, Eveliina | Hämäläinen, Eija-Riitta | Kiviranta, Ilkka | Lammi, Mikko J.

Article Type: Research Article

Abstract: One goal of functional tissue engineering is to manufacture scaffolds infiltrated with chondrocytes which are suitable for transplantation into the lesion areas of articular cartilage. Various research strategies are used to fabricate cartilage transplants which would have the correct phenotype, contain enough extracellular matrix components, and have structural and biomechanical properties equivalent to normal articular cartilage. We have investigated the suitability of viscose cellulose sponges as a scaffold for cartilage tissue engineering. The sponges were tested alone, or with recombinant human type II collagen cross-linked inside the material. Scanning electron microscopy and confocal microscopy were used to study the structure …of the scaffold during four weeks of cultivation. Cellulose and cellulose/recombinant type II collagen sponges were biocompatible for at least four weeks in cultivation, and gradual filling of the scaffold was observed. However, the constructs remained soft during the observation period, and were devoid of extracellular matrix composition typical for normal articular cartilage. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S29-S35, 2006

Authors: Schumann, D. | Kujat, R. | Nerlich, M. | Angele, P.

Article Type: Research Article

Abstract: Articular cartilage possesses little capacity for endogenous repair after having been damaged by disease or trauma. Various surgical procedures depending on ingrowth of mesenchymal stem cells into the defects showed repair with fibrocartilage which is of minor quality and less resistant against physical forces. New treatment options using Tissue Engineering strategies for cartilage repair showed intriguing results. Human mesenchymal stem cells (MSC) isolated from bone marrow are becoming increasingly recognized for their potential to generate different cell types and thereby function effectively in vitro or in vivo in tissue repair. Incorporation of MSCs in suitable tissue engineering scaffolds and culture …in chondrogenic medium can produce cartilage-like tissue. MSCs can be harvested from bone marrow by a small puncture of the iliac crest of patients. In contrast to chondral based repair this small procedure creates no additional harvest defect in the knee joints of the patient. Numerous publications show the beneficial influence of mechanobiological conditioning (e.g. mechanical compression, hydrostatic pressure, osmotic, shear, ultrasound) on the chondrogenic differentiation of dedifferentiated chondrocytes. In contrast to chondrocytes and cartilage explants there are few studies that examine the influence of mechanobiological stress on mesenchymal progenitor cells undergoing chondrogenesis. Using an in vitro aggregate culture system enhanced chondrogenesis of mesenchymal progenitor cells, detected by an increased extracellular matrix deposition of collagen and aggrecan, could be shown under repeated cyclic hydrostatic pressure. Similar results, with an increase in chondrogenic differentiation of mesenchymal progenitor cells could be detected, when the cells were loaded in three-dimensional matrices and subjected to cyclic, compressive load or low-intensity pulsed ultrasound. This review will summarize the current state of knowledge in the field of mechanobiological conditioning of mesenchymal stem cells and its possible clinical application. Show more

Keywords: Chondrogenesis, stem cells, bone marrow, mechanobiology, cartilage

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S37-S52, 2006

Authors: Amédée, J. | Guillotin, B. | Pallu, S. | Bareille, R. | Guignandon, A. | Bourget, Ch. | Durrieu, M.C. | Bordenave, L.

Article Type: Research Article

Abstract: In the field of osseous substitution, the possibilities being offered to the surgeons prove sometimes difficult to apply in particular in the case of great losses of osseous substance. For these reasons, it is necessary to develop innovative techniques to satisfy the request increasing for substitutes and to see appearing on the market solutions combining availability, perenniality and biosecurity of the implants. The implantation of stem cells in a biomaterial opens a way of development of therapeutic substitute. Moreover, in order to optimize the rehabitation of the biomaterials by the cells and the host tissues, the second approach consists in …modifying the surface of materials by the coating or the grafting of adhesive factors in order to stimulate their colonization. At least, one cannot consider a tissue mechanism of repair without a better knowledge of the respective role of the various cell populations implied in the rebuilding of this tissue and their cell to cell communication processes. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S53-S60, 2006

Authors: Matoušková, Eva | Brož, Ludomír | Štolbová, Vlasta | Klein, Leo | Kőnigová, Radana | Veselý, Pavel

Article Type: Research Article

Abstract: The tissue engineered skin should be composed of both dermal and epidermal layers. We combined cultured human allogeneic keratinocytes with acellular xenodermis prepared from pig xenografts. The resulting composite skin was termed recombined human/pig skin (RHPS), and could be cultured in both, undifferentiated and differentiated phenotype. The undifferentiated RHPS was grown submerged and formed 1–2 layers of keratinocytes. The differentiated phenotype (D-RHPS) was grown at the air-liquid interface and formed 5–20 cell layers similar to the normal epidermis, including the granular and horny layers. Undifferentiated RHPS has skin-like consistency and has been successfully used for treatment of burns and skin …defects using “upside-down” application. Donor sites and deep dermal burn wounds prepared by tangential excision or deep dermabrasion grafted with RHPS healed in the course of about one week after keratinocyte transplantation. Simple acellular xenodermis without keratinocytes can also be used as temporary cover for donor sites, small to medium leg ulcers and other skin defects. Xenodermis can be fully sterilized and stored at the room temperature. Show more

Keywords: Acellular xenodermis, human keratinocytes, recombined human/pig skin, wound grafting, burns

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S63-S71, 2006

Authors: Auxenfans, C. | Colloud, M. | Debard, A.L. | Braye, F.M. | Amini, M. | Allombert-Blaise, V. | Builles, N. | Claudy, A. | Damour, O.

Article Type: Research Article

Abstract: The clinical interest of using allogenic epidermal sheets (AES) has largely been shown [1,2,3]. As well as covering, they also stimulate healing, by simultaneously secreting numerous growth factors (GFs), although little is known on their mechanism of action. Our objectives were to: (a) devise a test for the efficacy of AES release, (b) select keratinocyte-secreting strains and optimal culture conditions. Three GFs were selected: IL-1α, IL-8 and VEGF. Three different keratinocyte strains were cultured for 3 and 6 days after confluence for 3 passages. Assays were performed after 3 h and 24 h+3 h after dispase treatment (AES conservation for …24 h then change of medium and sampling after 3 h). AES were found to secrete GFs in DMEM and the amounts were greater when cultured for 6 rather than 3 days after confluence. Each strain had different secretory patterns depending on passage and time in culture, this variability being explained by inter-individual heterogeneity. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S73-S83, 2006

Authors: Dezutter-Dambuyant, C. | Black, Annie | Bechetoille, Nicolas | Bouez, Charbel | Maréchal, Sylvie | Auxenfans, Céline | Cenizo, Valérie | Pascal, Pascale | Perrier, Eric | Damour, Odile

Article Type: Research Article

Abstract: The development of human skin models that have the same properties as genuine human skin is of particular significance. Very promising skin models are the three-dimensional artificial skin constructs, which, similar to genuine skin, consist of an epidermis of differentiated keratinocytes and a dermis. A skin equivalent based on a collagen–glycosaminoglycan–chitosan dermal substrate has been developed to meet the growing demand in tissue engineered skin equivalents. We used this model to investigate whether CD34-generated Langerhans/dendritic cell precursors could be integrated into this skin equivalent model and pursue their differentiation without addition of cytokine and growth factor. To address the issue …of dendritic cell (DC) differentiation, an endothelialized skin equivalent coculture model was used to study the behaviour of haematopoietic progenitor cells (HPC) in epidermal and dermal environments. CD34+ HPC were cultured for 6 days with GM-CSF, TGFβ1 and TNFα and seeded in the endothelialized skin equivalent at different time points to favour dermal or epidermal integration. This integration (after keratinocyte seeding, only and in absence of exogenous GM-CSF, TNFα, TGFβ1) gave rise both cutaneous DC, i.e. epidermal Langerhans cells (CD1a+ , HLA-DR+ ) and dermal DC (DC-SIGN+ , HLA-DR+ ) while endothelial cells are sufficiently activated to acquire HLA-DR expression. For the first time, the presence of a living dermal equivalent could provide a more complex environment integrating vascular components to study the differentiation of interstitial DC in a dermis equivalent. Such sophisticated skin equivalent may clarify some intriguing aspects of the numerous regulatory mechanisms controlling skin homeostasis. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S85-S94, 2006

Authors: Builles, Nicolas | Bechetoille, Nicolas | Justin, Virginie | Ducerf, Amélie | Auxenfans, Céline | Burillon, Carole | Sergent, Michèle | Damour, Odile

Article Type: Research Article

Abstract: Our objective was to formulate a medium for monolayer culture optimising both keratocyte growth and preservation of the keratocyte phenotype. Methods: An experimental matrix selected 14 media to test, using 7 components. Selection criteria were growth rates over 5 passages and expression of the CD34 marker. Results: Acetylcholine, insulin and vitamin C had no effect on growth and differentiation. The DMEM + Ham F12 1 : 1 based medium was selected for its initial effect on growth. At concentrations of 5 ng/ml, b-FGF improved the percentage of CD34+ cells without reducing growth rates. New-born calf serum (NCS) had a greater effect on …growth than foetal calf serum (FCS). We showed three major interactions: between b-FGF and IGF-1, FCS and IGF-1 and NCS and b-FGF. Conclusion: We selected the following medium, which provides optimal growth and preservation of the CD34+ phenotype: DMEM/HAM-F12 + 10% NCS + 5 ng/ml b-FGF + antibiotics. Show more

Keywords: Keratocytes, culture, medium

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S95-S104, 2006

Authors: Vinatier, C. | Guicheux, J. | Daculsi, G. | Layrolle, P. | Weiss, P.

Article Type: Research Article

Abstract: Tissue engineering is an emerging field of regenerative medicine which holds promise for the restoration of tissues and organs affected by chronic diseases, age-linked degeneration, congenital deformity and trauma. During the past decade, tissue engineering has evolved from the use of naked biomaterials, which may just replace small area of damaged tissue, to the use of controlled three-dimensional scaffolds in which cells can be seeded before implantation. These cellularized constructs aims at being functionally equal to the unaffected tissue and could make possible the regeneration of large tissue defects. Among the recently developed scaffolds for tissue engineering, polymeric hydrogels have …proven satisfactory in cartilage and bone repair. Major technological progress and advances in basic knowledge (physiology and developmental biology) are today necessary to bring this proof of concept to clinical reality. The present review focuses on the recent advances in hydrogel-based tissue engineered constructs potentially utilizable in bone and cartilage regenerative medicine. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S107-S113, 2006

Authors: Boura, C. | Kerdjoudj, H. | Moby, V. | Vautier, D. | Dumas, D. | Schaaf, P. | Voegel, J.-C. | Stoltz, J.-F. | Menu, P.

Article Type: Research Article

Abstract: Polyelectrolyte multilayer films were recently investigated to favour attachment of Human Vein Umbilical Endothelial Cells (HUVECs) on non-adhesive surfaces. In this study, we evaluated the initial adhesion of HUVECs after 3 h of seeding on two polyelectrolyte multilayer films ending by poly(D-lysine) (PDL) or poly(allylamine hydrochloride) (PAH). In order to obtain information about initial adhesion of HUVECs, cell morphology as well as the expression of β1 integrins, specific receptors of adhesion, were evaluated after 3 h of seeding on polyelectrolyte multilayer films. The data were also compared to PDL or PAH monolayers (polyelectrolytes terminating the multilayer architecture). The expression of …β1 integrins was not different, whatever are the studied surfaces. However, HUVECs spreading on polyelectrolyte multilayer films, in particular on PAH ending film, was more important as compared to polyelectrolyte monolayers or glass. In conclusion, the best initial adhesion conditions of HUVECs on polyelectrolyte films could not be elucidated, moreover the results suggested also that β1 integrins could only play a limited role. Show more

Keywords: Polyelectrolyte multilayers, endothelial cells, cell adhesion, atomic force microscopy, β1 integrins

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S115-S121, 2006

Authors: Kerdjoudj, H. | Boura, C. | Marchal, L. | Dumas, D. | Schaff, P. | Voegel, J.-C. | Stoltz, J.-F. | Menu, P.

Article Type: Research Article

Abstract: Decellularized allograft tissues have been identified as a potential extracellular matrix scaffold for tissue-engineered vascular substitutes. In order to improve the thromboresistance, it is necessary to pre-coat the intra-luminal vessel surface. Recently a new surface modification technique appeared, based on the alternate adsorption of positive and negative charged polyelectrolytes. Our objective was to develop an alternative vascular scaffold made of decellularized human umbilical arteries treated with a PAH/PSS polyelectrolyte multilayered film. The vessels luminal surfaces covered with the multilayer film were observed by electronic scanning microscopy. Our observations showed that the luminal surface is completely devoid of ECs following treatment …with trypsin. A top view of the coated artery indicated that the multilayer uniformly covered internal surface of the vessels. The successful of the multilayer correct deposition and retention on the arterial wall were controlled by confocal microscopy using a fluorescent polyelectrolyte (rhodamine-PAH). The data suggest that decellularized cryopreserved arteries represent a potential scaffold for further vascular tissue engineering efforts. Moreover, the multilayer films can be used to coat biological surfaces and following the terminated layer (PAH or PSS), favour the cell adhesion or cell resistance. Show more

Keywords: Cardiovascular engineering, vascular grafts, umbilical arteries, surface modification, thin polyelectrolyte multilayer film

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S123-S129, 2006

Authors: Vaquette, C. | Fawzi-Grancher, S. | Lavalle, P. | Frochot, C. | Viriot, M.-L. | Muller, S. | Wang, X.

Article Type: Research Article

Abstract: Nowadays, synthetic biodegradable polymers, such as aliphatic polyesters, are largely used in tissue engineering. They provide several advantages compared to natural materials which use is limited by immunocompatibility, graft availability, etc. In this work, poly(L-lactic) acid (PLLA), poly(DL-lactic) acid (PDLA), poly-ε-caprolactone (PCL), poly(L-lactic)-co-caprolactone (molar ratio 70/30) (PLCL) were selected because of their common use in tissue engineering. The membranes were elaborated by solvent casting. Membrane morphology was investigated by atomic force microscopy. The membranes were seeded with human fibroblasts from cell line CRL 2703 in order to evaluate the biocompatibility by the Alamar blue test. The roughness of the membranes …ranged from 4 nm for PDLA to 120 nm and they presented very smooth surface except for PCL which beside a macroscopic structure due to its hydrophobicity. Human fibroblasts proliferated over 28 days on the membranes proving the non-in vitro toxicity of the materials and of the processing method. A further step will be the fabrication of three-dimensional scaffold for tissue engineering and the treatment of the scaffolds to augment cell adhesion. Show more

Keywords: Biocompatibility, fibroblast, biodegradable polymer, proliferation, scaffold

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S131-S136, 2006

Authors: Shalaw, Fawzi-Grancher | Slimani, Said | Kolopp-Sarda, M.N. | Marchand, Michel | Faure, G. | Stoltz, Jean-François | Muller, Sylvaine

Article Type: Research Article

Abstract: It is well known today that mechanical forces are one of the important factors that induce a variety of cellular responses including morphological changes, protein synthesis, and gene expression and which are involve in tissue remodelling. We studied the effect of uniaxial cyclic stretching on the proliferation, collagens, and tenascin C mRNA expression of fibroblasts under different concentrations of foetal bovine serum. Proliferation was studied by cell cycle analysis, mRNA expression of collagen and tenascin C was studied by RT-PCR. Human fibroblasts were grown in silicon sheet coated with 1% gelatin. Cyclic stretching (5% elongation) was applied at 0.5 Hz …(30 cycle/min), for 24 h with two concentrations of the serum (0.5%, 10% FBS). We showed that stretching enhances the synthesis of collagen and tenascin C, but do not act on the proliferation. In contrast, higher concentration of serum enhances the proliferation. These findings suggest that both mechanical stretching and serum concentration can modulate proliferation and extra cellular matrix synthesis in human fibroblasts. Show more

Keywords: Cyclic stretching, FBS, proliferation, extracellular matrix synthesis

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S137-S144, 2006

Authors: Silva, João N. | Filipe, Paulo | Morlière, Patrice | Mazière, Jean-Claude | Freitas, João P. | Cirne de Castro, José L. | Santus, René

Article Type: Research Article

Abstract: Photodynamic therapy (PDT) by porphyrins and related tetrapyrrole derivatives is an emerging new treatment modality of tumors of lung, eosophagus and skin and of age-related macular degeneration. Phase III clinical trials for other applications such as re-stenosis after angioplasty are also underway. Under systemic conditions, the transport of porphyrin photosensitizers by serum low density lipoproteins and their specific delivery to tumor cells and vasculature is a determinant of treatment effectiveness. However, this effectiveness can be improved by increasing the selectivity of the photosensitizer uptake by tumors and by using photosensitizers absorbing light in the 660–800 nm range where tissues have …the highest transmittance. Another treatment showing great promise is the PDT of skin cancers after topical application of the protoporphyrin IX precursor delta-aminolevulinic acid (or its ester forms). In all the cases, the photosensitizers should be rapidly excreted to avoid a long lasting skin photosensitivity. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S147-S154, 2006

Authors: Cattan, Valérie | Kakou, Augustine | Louis, Huguette | Lacolley, Patrick

Article Type: Research Article

Abstract: Stiffening of large arteries is considered as an independent predictor of cardiovascular events. This article summarizes recent theories on the mechanisms contributing to arterial stiffness involving extracellular matrix proteins, endothelial and smooth muscle cells, cell–matrix interactions, and genetic background. Despite the important role of genetic factors in essential hypertension, little is known about the genetic of arterial stiffness. In the future, candidate genes approaches will allow to determine the cellular and molecular mechanisms of arterial stiffness. A review of different strategies aimed at lowering arterial stiffness and potentially reducing cardiovascular risk are presented. Lifestyle changes and antihypertensive drugs have showed …beneficial effects in reversing stiffness. New emerging tools as gene therapy and molecules involved in matrix attachments or crosslink of collagen may be promising. Therapeutic trials using such strategies will be necessary to demonstrate their impact on morbidity and mortality. Show more

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S155-S161, 2006

Authors: Li, Yin-Ping | Latger-Canard, Véronique | Marchal, Luc | Li, Na | Ou-Yang, Jing-Ping | Stoltz, Jean-François

Article Type: Research Article

Abstract: Immune homeostasis is important for the protection of a host from pathogen aggression, as well as for preventing autoimmunity. Dendritic cells (DCs), the most potent antigen presenting cells, are critical in innate, adaptive immunity and in central tolerance. Recently, their involvement in peripheral tolerance has been shown. Whether DCs induce immunity or tolerance depends on their state of maturation. Different subsets of tolerogenic DCs have been identified in vivo, either in physiological, or pathological conditions, such as tumors, or GVHD. Moreover, tolerogenic DCs can be generated in vitro, by using different culture conditions, such as IL-10 or TGF-β. In our …study, we obtained tolerogenic DCs, by culturing them in the presence of human mesenchymal stem cells (MSCs). Show more

Keywords: Dendritic cells (DCs), tolerogenic DCs, immunity, tolerance, mesenchymal stem cells (MSCs)

Citation: Bio-Medical Materials and Engineering, vol. 16, no. 4, pp. S163-S170, 2006