Chronic respiratory pathologies are very common in sports or leisure horses (15-20 % of horses are affected). Despite high pulmonary capacity, even a mild respiratory problem can have consequences for the work and performance of the horse due to intolerance to effort. These pathologies can become debilitating and have an adverse economic and emotional impact on the equine chain due to convalescence periods and premature careers. The treatments available to date in the equine chain are only symptomatic and are mainly based on changes in the animal’s environment. Treatment with steroidal anti-inflammatory drugs (corticoids) can help reduce lung inflammation. On the other hand, no treatment will be able to repair the pulmonary lesions suffered.Mesenchymal stem cells (MSCs) have promising characteristics for regenerative medicine: the sampling location necessary for the purification and production of these cells is easily accessible; these cells can be amplified in the laboratory in large quantities and do not pose any ethical or technical problems of use. Transplanted in vivo, MSCs can migrate to the lesion to be treated and modulate the secretion of various cytokines to help reduce inflammation in the injured tissue. Although these cells alone have restorative capabilities, they have a propensity to die when implanted in a hostile environment limiting their regenerative potential. As a result, we have sought to develop approaches to counteract this inconvenience. Thus, we have shown in our team (Quittet et al., Acta Biomat. 2015) but also in collaboration with NORMANDY BIOTECH that associating these cells with a micro-support (which will later be called NB) adds value to the future of MSCs since these biomaterials improve cell adhesion and survival. Indeed, the NBs, which, having an extracellular matrix surface with adhesion molecules, have the ability to create an adequate three-dimensional structure for the attachment and differentiation of grafted cells.The ultimate objective of the project is to propose an innovative approach to cell therapy to treat emphysema one of the respiratory pathologies most encountered in equine clinics and which could potentially also be of interest to the human clinic. This objective requires proof of concept on murine models. Therefore, in this project we propose to evaluate the value of combining MSCs with NB as a regenerative treatment of experimentally induced emphysema in mice. Recall that we have previously validated the interest of such a regenerative strategy in cerebral pathologies, which later enabled the transfer of this know-how to the company NORMANDY BIOTECH, which since commercialises this product as part of the treatment of joint diseases in horses.After developing the model of emphysema in rodent, we will pay particular attention to demonstrating the feasibility of systemic NB administration, the safety and therapeutic efficacy of this treatment combining MSC and NB. These experimental data will provide proof of concept that will allow us to consider developing in a second stage 1/experimental studies in horses (emphysema will be induced experimentally in animals) and 2/clinical studies in horses with this pulmonary pathology. We propose to call this new therapeutic agent Respi'NB.