Search

Background: In mammals, amino acid metabolism has evolved to control immune responses. Tryptophan (Trp) is the rarest essential amino acid found in food and its metabolism has evolved to be a primary regulatory node in the control of immune responses. Celiac disease (CeD) is a developed immunological condition caused by gluten intolerance and is linked to chronic small intestine enteropathy in genetically predisposed individuals. Dendritic cells (DCs), serving as the bridge between innate and adaptive immunities, can influence immunological responses in CeD through phenotypic alterations. Objective: This review aims to highlight the connection between Trp metabolism and tolerogenic DCs, and the significance of this interaction in the pathogenesis of CeD. Results: It is been recognized that various DC subtypes contribute to the pathogenesis of CeD. Tolerogenic DCs, in particular, are instrumental in inducing immune tolerance, leading to T‐reg differentiation that helps maintain intestinal immune tolerance against inflammatory responses in CeD patients and those with other autoimmune disorders. T‐regs, a subset of T‐cells, play a crucial role in maintaining intestinal immunological homeostasis by regulating the activities of other immune cells. Notably, Trp metabolism, essential for T‐reg function, facilitates T‐reg differentiation through microbiota‐mediated degradation and the kynurenine pathway. Conclusion: Therefore, alterations in Trp metabolism could potentially influence the immune response in CeD, affecting both the development of the disease and the persistence of symptoms despite adherence to a gluten‐free diet. [ABSTRACT FROM AUTHOR]

Objective(s): Design and construction of biocompatible and biodegradable scaffolds are among the main goals of tissue engineering. Recently, use of nano-hydroxyapatite as a bioactive bioceramic agent with high similarity to the mineral phase of the human bone tissue, in combination with biodegradable polymers and implant coatings has attracted the attention of researchers in the field of biomaterial sciences. The present study aimed to assess the differentiation of bone marrow stromal cells (BMSCs) in osteoblast-like cells on the chitosan/polyethylene oxide (PEO)/nano-hydroxyapatite scaffold in mature rats. Materials and Methods: Chitosan and PEO solution with the weight ratio of 80:20 and 70:30 were prepared, and 2% weight of nano-hydroxyapatite was added. Nanofibers were prepared using the electrospinning method, and the morphology was studied using scanning electron microscopy (SEM). Afterwards, the BMSCs of mature rats were cultured on nanofibers and differentiated by adding a differentiation medium. The survival of the differentiated cells was evaluated at the end of the first, second, and third week using acridine orange staining, and the morphology of the differentiated cells exposed to nanofibers was assessed using SEM. Results: The mean diameter of the nanofibers with the ratio of 80:20 was 150±17 nanometers. The differentiation of BMSCs into the osteoblast-like cells on nanofibers was confirmed using Alizarin red staining. The results indicated a significant decrease in the survival of the differentiated cells in the nanofiber groups by the end of the third week of differentiation compared to the control samples. Conclusion: According to the results, BMSCs could be differentiated into osteoblast-like cells in the presence of the chitosan/PEO nanofibers containing nano-hydroxyapatite. [ABSTRACT FROM AUTHOR]

Objective (s): Several methods have been proposed for repairing defects and damages, one of which is cell therapy. Bone marrow stromal cells seem to be suitable for this purpose. On the other hand, many biometric materials are used to improve and correct the defects in the body. Nanofibers are widely used in the medical industry, especially in tissue engineering, as scaffolds in wound healing and wound dressing. Chitosan/ polyethylene oxide nanofibers can be a suitable replacement for routine wound coverages. Hence, this study was conducted to present a combination of these methods. Materials and Methods: Chitosan/polyethylene oxide nanofibers and thin films of chitosan were produced and optimized by electron microscopy, on which the bone marrow stromal cells were then cultivated. Interactions between the cells and these biomaterials were investigated through viability, morphology, immunocytochemistry and electron microscopy of cells after 6 days. All data were analyzed using Student's t-test and one-way ANOVA tests in SPSS version 16. P<0.05 was considered significant. Results: It seems that the high viscosity of chitosan prevents the formation of nanofibers, while chitosan/polyethylene oxide solutions with 80/20 and 90/10 ratios produce perfect, regular, bead free and non-toxic nanofibers with average diameter of 240±10 and 220±10 nm, respectively. The results of immunocytochemistry and viability showed that the cells had relatively high proliferation on the thin chitosan membranes, while the results of the electron microscopy showed that the morphology of cells was better on the nanofibers than on the thin membrane of chitosan. Conclusion: Since bone marrow stromal cells were grown well on chitosan-nanofibers, each of them alone was used in the therapeutic methods. It is better to consider a combination of two methods as the treatment method, especially in tissue engineering and cell therapy. [ABSTRACT FROM AUTHOR]