The immunomodulatory potential of murine adipose-derived mesenchymal stem cells is enhanced following culture on chitosan film.

INTRODUCTION: Recent studies show that the paracrine immunomodulatory effects of mesenchymal stem cells (MSCs) are mediated by the secretion of interleukin-10 (IL-10), transforming growth factor-beta (TGF ß), and nitric oxide (NO). The preconditioning of MSCs improves their immunomodulatory characteristics. Chitosan is a biopolymer with low toxicity and biodegradability, used as a membrane for MSCs three-dimensional culture. The present study aimed to evaluate the levels of immunomodulatory mediators of mesenchymal cells cultured on the chitosan film. MATERIALS & METHODS: MSCs were isolated from abdominal adipose tissue of BALB/c mice. Flow cytometry and differential culture medium were used to confirm the identity of isolated mesenchymal stem cells. The MSCs were divided into three groups; The first group was treated with 10 ng/mL LPS. The second group was seeded in the flasks coated with the chitosan film (3% w/v). The last group was cultured in the flasks without any preconditioning. After 72 h, IL-10, TGF-ß, and NO concentrations were measured in the conditioned media. In addition, the arginase activity in mesenchymal stem cells was measured using a colorimetric method. RESULTS: The proliferative spindle-shaped MSCs formed several three-dimensional spheroids on the chitosan film. It was shown that the level of TGF-ß and IL-10 were increased significantly after treatment with LPS (P = 0.02) and spheroid formation (P = 0.01). In addition, the arginase activity was enormously augmented in spheroids compared to controls (7.13-fold increase; 1.71 ± 0.08 and 0.24 ± 0.01 respectively; P = 0.021). On the other hand, the LPS treatment but not the culture on chitosan film increased the NO level significantly (P = 0.02 and P = 0.14, respectively). CONCLUSION: Using chitosan film as a three-dimensional culture strategy significantly affects the production of immunosuppressive factors by MSCs in vitro through increased secretion of TGF-ß and IL-10 and arginase activity.

Naturally occurring biological macromolecules-based hydrogels: Potential biomaterials for peripheral nerve regeneration.

Despite the recent advances in the treatment strategies of peripheral nerve system defects, peripheral nerve injury (PNI) is still one of the most important health issues with increasing incidence worldwide. The most commonly used treatment approaches are allografts, xenografts, and autologous, which have some drawbacks, including complications, limited source of the donor tissue, tubular collapse, and scar tissue formation. In this context, regenerative medicine has been introduced as a powerful approach to improve the healing process and obtain acceptable functional recovery in the injury site using living cells, scaffold, and bioactive (macro-) molecules. Amongst them, scaffold as a three-dimensional (3D) support biomaterial, structurally bridged the gap or site of injury in order to provide physical and chemical cues to promote correct reinnervation and functional regeneration. Amongst different scaffolding biomaterials, naturally occurring biological macromolecules (more especially proteins and polysaccharides)-based hydrogels exhibited promising results due to their fascinating physicochemical, as well as physiologically relevant properties. This review highlights the recent progress in the development of natural hydrogels-based neural scaffolds. Furthermore, PNI healing process, current status, and challenges are also shortly discussed.