Preparation and in vitro Evaluation of Injectable Alginate/Thiolated Chitosan Hydrogel Scaffold for Neural Tissue Engineering

Introduction: Spinal cord injuries are one of the main causes of disability with devastating neurological consequences and secondary conflicts in other organs. Tissue engineering and regenerative medicine have been recognized as novel, promising methods in the treatment of tissue injuries, especially in neurological damage in recent decades. Hydrogels have the advantage of compatibility with damaged tissue, and injectable hydrogels can be applied in minimally invasive surgeries. This study aimed to evaluate an injectable hydrogel-based scaffold consisting of thiolated chitosan and alginate for neural tissue regeneration. Materials and Methods: In the present study, an injectable hydrogel-based containing thiolated chitosan and alginate was prepared. Microbiology and pH tests were performed. Microstructural properties and porosity of scaffold were evaluated by scanning electron microscope (SEM). The swelling /shrinkage ratio and rates of biodegradation were also conducted. Finally, the viability of L929 cells on the scaffold was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: Thiolated chitosan/ alginate hydrogel had low pH with no contamination. SEM showed hydrogel had a porous microstructure with a mean pore diameter of 21.89 ± 0.32 μm which is suitable for cell culture. Furthermore, according to MTT test results, this hydrogel was biocompatible. Conclusion: Thiolated chitosan/ alginate hydrogel is convenient for application in neural tissue engineering based on its structural properties and its ability to support cell proliferation. According to the in vitro analysis, it can also be used as a scaffold to create a suitable environment for increasing cell viability

Transcriptomic and in vivo approaches introduced human iPSC-derived microvesicles for skin rejuvenation

Abstract The skin undergoes the formation of fine lines and wrinkles through the aging process; also, burns, trauma, and other similar circumstances give rise to various forms of skin ulcers. Induced pluripotent stem cells (iPSCs) have become promising candidates for skin healing and rejuvenation due to not stimulating inflammatory responses, low probability of immune rejection, high metabolic activity, good large-scale production capacity and potentials for personalized medicine. iPSCs can secrete microvesicles (MVs) containing RNA and proteins responsible for the normal repairing process of the skin. This study aimed to evaluate the possibility, safety and effectiveness of applying iPSCs-derived MVs for skin tissue engineering and rejuvenation applications. The possibility was assessed using the evaluation of the mRNA content of iPSC-derived MVs and the behavior of fibroblasts after MV treatment. Investigating the effect of microvesicle on stemness potential of mesenchymal stem cells was performed for safety concerns. In vivo evaluation of MVs was done in order to investigate related immune response, re-epithelialization and blood vessel formation to measure effectiveness. Shedding MVs were round in shape distributed in the range from 100 to 1000 nm in diameter and positive for AQP3, COL2A, FGF2, ITGB, and SEPTIN4 mRNAs. After treating dermal fibroblasts with iPSC-derived MVs, the expressions of collagens Iα1 and III transcripts (as the main fibrous extracellular matrix (ECM) proteins) were upregulated. Meanwhile, the survival and proliferation of MV treated fibroblasts did not change significantly. Evaluation of stemness markers in MV treated MSCs showed negligible alteration. In line with in vitro results, histomorphometry and histopathology findings also confirmed the helpful effect of MVs in skin regeneration in the rat burn wound models. Conducting more investigations on hiPSCs-derived MVs may lead to produce more efficient and safer biopharmaceutics for skin regeneration in the pharmaceutical market