Cell therapy is a promising strategy for treating neurological pathologies but requires invasive methods to bypass the blood-brain barrier restrictions. The nose-to-brain route has been presented as a direct and less invasive alternative to access the brain. The primary limitations of this route are low retention in the olfactory epithelium and poor cell survival in the harsh conditions of the nasal cavity. Thus, using chitosan-based hydrogel as a vehicle is proposed in this work to overcome the limitations of nose-to-brain cell administration. The hydrogel's design was driven to achieve gelification in response to body temperature and a mucosa-interacting chemical structure biocompatible with cells. The hydrogel showed a 95% biocompatibility with 2D and 3D cultures of mesenchymal stromal cells. Additionally, the viability, stability, and migration capacity of oligodendrocyte precursor cells (OPCs) within the hydrogel were maintained in vitro for up to 72 hours. After the intranasal administration of the OPCs-containing hydrogel, histological analysis showed the presence of viable cells in the nasal cavity for up to 72 hours post-administration in healthy athymic mice. These results demonstrate the hydrogel's capacity to increase the residence time in the nasal cavity while providing the cells with a favorable environment for their viability. This study presents for the first time the use of thermosensitive hydrogels in nose-to-brain cell therapy, opening the possibility of increasing the delivery efficiency in future approaches in translational medicine. STATEMENT OF SIGNIFICANCE: : This work highlights the potential of biomaterials, specifically hydrogels, in improving the effectiveness of cell therapy administered through the nose. The nose-to-brain route has been suggested as a non-invasive way to directly access the brain. However, delivering stem cells through this route poses a challenge since their viability must be preserved and cells can be swept away by nasal mucus. Earlier attempts at intranasal cell therapy have shown low efficiency, but still hold promise to the future. The hydrogels designed for this study can provide stem cells with a biocompatible environment and adhesion to the nasal atrium, easing the successful migration of viable cells to the brain.

Background: Multiple sclerosis (MS) is a neurodegenerative disorder characterized by progressive motor and cognitive impairments, affecting millions worldwide. It significantly reduces patients’ quality of life and imposes a burden on health systems. Despite advances in understanding MS, there is no cure, highlighting the need for effective therapeutic strategies. Preclinical animal models are critical for gaining insights into MS pathophysiology and treatments. However, these models fail to fully replicate the complexity of human MS, making it essential to choose appropriate models and behavioral tests to evaluate their efficacy. Purpose: This review examines various motor and cognitive behavioral tests used in preclinical MS models, discussing their strengths and limitations. The goal is to guide researchers in selecting the most appropriate tests for their models, while providing insights into how these tests are performed and analyzed. Methods: We reviewed motor and cognitive behavioral tests used in MS models, detailing test procedures and evaluating their advantages and disadvantages. Results: This review offers a comprehensive overview that aids researchers in choosing the most suitable tests for their studies, improving the accuracy and reliability of preclinical MS research. Conclusions: Understanding the strengths and limitations of these tests is crucial for making informed decisions, leading to better experimental designs and, ultimately, more effective therapeutic interventions for MS.

Background: Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS), characterised by inflammation, demyelination, and progressive neurodegeneration. Although current disease-modifying therapies (DMTs) can reduce relapse rates and inflammatory activity, they rarely stop long-term progression or repair neurological damage. In recent years, cell-based therapies have emerged as promising approaches to promote immune regulation and neuroregeneration in MS. Methods: This review summarises the current clinical evidence from studies in humans investigating cell-based treatments for MS, including autologous haematopoietic stem cell transplantation (AHSCT), mesenchymal stem cells (MSCs), and neural stem or progenitor cells (NSCs). A systematic literature search was performed using PubMed, Scopus, and ClinicalTrials.gov, focusing on human clinical trials that met specific inclusion criteria. Results: Prevailing findings show that AHSCT provides the most consistent benefit, achieving long-term immune reconstitution and remission in patients with highly active relapsing–remitting MS (RRMS), although it carries procedural risks. MSC therapies have demonstrated good safety and biological activity, especially when delivered intrathecally (IT) in progressive MS, though clinical results remain variable. Conclusions: NSC-based treatments are still at an early stage of clinical research but show potential for CNS repair. The main limitations across studies include differences in protocols, small sample sizes, and short follow-up periods. Further large-scale, randomised controlled trials are needed to confirm long-term efficacy, define optimal delivery methods, and establish standardised clinical protocols.