Reconstruction d'un modèle vésical par génie tissulaire et caractérisation

Le système urinaire a pour objectif l’élimination des produits du catabolisme sous forme d’urine. Cette fonction permet au sang d’être épuré en permanence et de maintenir ainsi l’équilibre de la composition sanguine (homéostasie). Plus précisément, la vessie est un réservoir extensible et étanche, responsable de l’emmagasinage de l’urine à basse pression, avant qu’elle soit évacuée hors de l’organisme. Diverses pathologies peuvent compromettre ces propriétés et endommager gravement le haut appareil urinaire. La confection d’une néovessie est alors essentielle pour assurer une collecte à basse pression de l’urine. La reconstruction vésicale par les techniques de chirurgie est associée à des complications cliniques significatives, causées principalement par l’absence de protection contre l’urine, normalement assurée par un épithélium hautement spécialisé : l’urothélium. Contrairement aux débuts de l’ingénierie tissulaire, pendant lesquels l’organisation cellulaire et moléculaire étaient relativement négligées, celles-ci sont aujourd’hui fortement prises en compte. C’est pourquoi cette technique fait appel à diverses matrices et aux cellules de l’hôte pour reproduire un substitut aussi conforme que possible au tissu natif. Toutefois, à ce jour, aucun modèle de substitution n’a été en mesure de pallier aux limites précédemment documentées. La complexité du remplacement vésical motive donc notre équipe à rechercher un substitut alternatif plus adapté cliniquement. L’objectif de ce projet de recherche était la mise au point de nouvelles méthodes pour parvenir à l’élaboration d’un substitut vésical comparable à la muqueuse d’une vessie native, puis la caractérisation de notre modèle aussi bien au plan structural que fonctionnel. Á partir de tissu porcin, plusieurs types cellulaires composant la paroi vésicale sont extraits simultanément puis caractérisés in vitro. Les cellules mésenchymateuses et urothéliales évoluent alors dans une culture tridimensionnelle pour former par génie tissulaire un tissu manipulable. La caractérisation de notre modèle vésical légitimise cette méthode qui semble très prometteuse pour répondre aux besoins dans le domaineThe purpose of the urinary tract is to ensure the evacuation of catabolic products in urine form. This function permits to preserve the equilibrium and consistency of the blood components (homeostasis). More precisely, the bladder is a watertight and compliant reservoir in charge of urine storage at low pressure, before its evacuation out of the organism. The bladder is subject to various pathologies, which could compromise its specific properties and damage the upper urinary tract. Therefore, the elaboration of a new reservoir is essential to collect the urine at low pressure. Surgical reconstruction is associated to significant complications, principally due to the lack of protection against urine, physiologically ensured by the highly specialized uro-eptithelium. Contrarily to the beginning of tissue engineering, cellular and molecular organizations are strongly considered nowadays. It is the reason why this discipline needs different matrices and host cells to reproduce a substitute conform to the original organ. But to date, no bioengineered models were able to completely overcome the limitations previously reported. The complexity of the vesical replacement remained a major challenge that led our team to research a more efficient bladder substitute. This project describes the approaches elaborated to achieve a vesical substitute comparable to the bladder mucosa. In addition, the structural and functional properties of our in vitro reconstructed models will be characterized with the use of different techniques. Based on our previous studies, several cellular types were isolated from the bladder wall, and then characterized in vitro. Using specific techniques of tissue-engineering, bladder mesenchymal and urothelial cells evolve in a three-dimensional culture to produce a tissue easy to handle. The maturation degree of our reconstructed models reached satisfactory characteristics to meet the need in the bladder regenerative field, and could led to better post-surgical results

Removal of organic matter and polyphenols in the olive oil mill wastewater by coagulation-flocculation using aluminum sulfate and lime.

This work aims to treat the liquid discharges from the olive oil crushing units to protect the receiving environments by the coagulation-flocculation process using lime and aluminum sulfate as chemical coagulants. We proceed by studying the effectiveness of the coagulation-flocculation technique in eliminating organic matter and polyphenols that characterize our samples and the possibility of reusing the treated wastewater in irrigation.Analysis shows that adding 1.7 g/l aluminum sulfate can eliminate 58% of COD, 23% of TSS, and 24% of polyphenols, producing 21g/l of sludge, and eliminating 52% of COD, 48% of TSS, and 72% Of polyphenols requires the addition of 20 g/l of lime, but 25 g/l of sludge is produced. Combining two coagulants (1.7 g/l of aluminum sulfate and 20 g/l of lime) reduces 64 % of COD, 72 % of TSS, and 62 % of polyphenols, with the sludge is 29g/l. The germination test by cucumber seeds showed the validity of the use of treated olive oil wastewater in agricultural irrigation

Anticancer properties of chitosan on human melanoma are cell line dependent

Purpose: Chitosan, a natural macromolecule, is widely used in medical and pharmaceutical fields because of its distinctive properties such as bactericide, fungicide and above all its antitumor effects. Although its antitumor activity against different types of cancer had been previously described, its mechanism of action was not fully understood. Materials and methods: Coating of chitosan has been used in cell cultures with A375, SKMEL28, and RPMI7951 cell lines. Adherence, proliferation and apoptosis were investigated. Results: Our results revealed that whereas chitosan decreased adhesion of primary melanoma A375 cell line and decreased proliferation of primary melanoma SKMEL28 cell line, it had potent pro-apoptotic effects against RPMI7951, a metastatic melanoma cell line. In these latter cells, inhibition of specific caspases confirmed that apoptosis was effected through the mitochondrial pathway and Western blot analyses showed that chitosan induced an up regulation of pro-apoptotic molecules such as Bax and a down regulation of anti-apoptotic proteins like Bcl-2 and Bcl-XL. More interestingly, chitosan exposure induced an exposition of a greater number of CD95 receptor at RPMI7951 surface, making them more susceptible to FasL-induced apoptosis. Conclusion: Our results indicate that chitosan could be a promising agent for further evaluations in antitumor treatments targeting melanoma

Comparative assessment of groundwater quality challenges confronting Mediterranean coastal aquifers: A synoptic review

Coastal aquifers, essential for agriculture, domestic, and industrial water supply, face significant sustainability challenges, particularly in Mediterranean regions, due to the adverse effects of human activities, climatic threats, and natural geological conditions causing salinization. This paper synthesizes findings from studies on three Mediterranean coastal aquifers— the Pleistocene aquifer in the Gaza Strip, the karstic aquifer in Bokkoya, and the MioPlio-Quaternary aquifer in Djeffara of Medenine—highlighting the escalating deterioration due to over-exploitation and arid conditions. It compares the methodologies used in these studies, such as statistical analysis, geostatistical modeling, and groundwater quality indices, to assess groundwater quality and address salinization challenges. This review aims to identify methodological limitations and propose strategies to fill research gaps, particularly in combating seawater intrusion, to enhance the sustainable management of these critical water resources

Élaboration et caractérisation d'un équivalent vésical dans le contexte de la bioingénierie

Le système urinaire a pour objectif l'évacuation des produits du catabolisme sous forme d'urine. Cette fonction permet au sang d'être épuré en permanence et de préserver ainsi l'équilibre de la composition sanguine (homéostasie). De nombreuses pathologies touchent la vessie et le manque de tissu autologue ayant des propriétés similaires à cette dernière constitue une limite importante à sa reconstruction. Contrairement aux débuts du génie tissulaire, l'organisation cellulaire et moléculaire est aujourd'hui fortement prise en compte, c'est pourquoi cette technique fait appel à diverses matrices et aux cellules de l'hôte pour reproduire un substitut conforme au tissu natif. Lors de la conception d'une néovessie, l'objectif est d'imiter la structure de la paroi vésicale ainsi que l'organisation de l'urothélium, responsable de l'étanchéité contre l'urine. Ce mémoire a donc pour but de placer le modèle que nous proposons pour la reconstruction vésicale, dans le contexte du génie tissulaire et de ses limites actuelles

Tissue Engineering of Urinary Bladder and Urethra: Advances from Bench to Patients

Urinary tract is subjected to many varieties of pathologies since birth including congenital anomalies, trauma, inflammatory lesions, and malignancy. These diseases necessitate the replacement of involved organs and tissues. Shortage of organ donation, problems of immunosuppression, and complications associated with the use of nonnative tissues have urged clinicians and scientists to investigate new therapies, namely, tissue engineering. Tissue engineering follows principles of cell transplantation, materials science, and engineering. Epithelial and muscle cells can be harvested and used for reconstruction of the engineered grafts. These cells must be delivered in a well-organized and differentiated condition because water-seal epithelium and well-oriented muscle layer are needed for proper function of the substitute tissues. Synthetic or natural scaffolds have been used for engineering lower urinary tract. Harnessing autologous cells to produce their own matrix and form scaffolds is a new strategy for engineering bladder and urethra. This self-assembly technique avoids the biosafety and immunological reactions related to the use of biodegradable scaffolds. Autologous equivalents have already been produced for pigs (bladder) and human (urethra and bladder). The purpose of this paper is to present a review for the existing methods of engineering bladder and urethra and to point toward perspectives for their replacement