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

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